Echinacea purpurea

BACKGROUND: Echinacea purpurea is widely utilized in dietary supplements, nutraceuticals, and herbal medicine, yet its effectiveness and safety for children remain debated. OBJECTIVE: To evaluate the effectiveness and safety of E. purpurea in the treatment of upper respiratory tract infection (URTI) and otitis media (OM) in children. DATA SOURCES: Embase, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, PubMed from January 2000 to December 2023. METHODS: This systematic review and meta-analysis were conducted and reported according to the PRISMA 2020 Checklist and Cochrane Training 2022 guidelines. RESULTS: 9 randomized controlled trials with 1518 participants in the treatment group, 1651 participants in the placebo control group, met the selection criteria. Products derived from E. purpurea are highly diverse, utilizing different plant parts such as roots, leaves, and flowers, available in various dosage forms like capsules and extracts, and manufactured in numerous countries worldwide. Risk of bias was assessed according to the PEDro scale with 3 studies of excellent quality, 5 studies of high quality and 1 study of moderate quality. The meta-analysis found that E. purpurea significantly benefits URTI, reducing treatment duration (SMD = -0.19, 95 % CI [-0.30; -0.09], p < 0.01), incidence (RR = 0.81, 95 % CI [0.75; 0.87]), and antibiotic use (RR = 0.18, 95 % CI [0.13; 0.25], p < 0.01). However, adverse events were moderately increased (RR = 1.38, 95 % CI [1.08; 1.78]), though generally mild. For OM, E. purpurea lowered episode incidence (RR = 0.56, 95 % CI [0.44; 0.73], p < 0.01) but did not shorten treatment duration (p = 0.10). Its effectiveness may be limited due to OM's bacterial etiology, often requiring antibiotics. While E. purpurea may help reduce recurrence, it is unlikely to speed recovery. Further research on optimal formulations and dosages is needed. The publication bias of pooled results as assessed by the funnel plot showed that the studies had certain bias, largely due to heterogeneity between studies. CONCLUSION: The meta-analysis of nine studies found that E. purpurea was effective in reducing the duration of treat

Upper respiratory tract infections (URTIs) are a prevalent health issue, causing considerable morbidity. Despite the availability of conventional treatments, there is an increasing interest in natural products due to their potential antiviral and immunomodulatory benefits. This study aims to evaluate the efficacy of an ELA blend (E-Echinacea purpurea, L-Lonicera cerulea, A-Aronia melanocarpa) in preventing and alleviating the symptoms of URTIs. Additionally, the study examines the blend's antiviral and immunomodulatory effects both in vitro and through a clinical trial. A randomized, double-blind, placebo-controlled trial involved 61 participants prone to URTIs, with a 60-day treatment and follow-up period. A placebo group later received the ELA blend for 60 days. The ELA blend significantly reduced the incidence of URTIs during the observation period (2 vs. 8; p = 0.044) and, in particular, throat-related symptoms (8 vs. 16; p = 0.038). Analyses of PBMCs showed that baseline production of the cytokines IFN-γ (p = 0.020), IL-1β (p = 0.004), IL-2(p < 0.001), IL-6 (p < 0.001), and TNF-α (p < 0.001) increased after ELA blend treatment. Moreover, the ELA blend modulated cytokine production in response to PHA-L stimulation, decreasing IFN-γ (p = 0.008) and IL-2 (p = 0.012) while increasing IL-1β (p = 0.005). Following R848 stimulation, the ELA blend enhanced the production of INF-α (p = 0.012) and IL-2 (p = 0.025), and decreased IL-1β (p < 0.001), IL-6 (p < 0.001), and TNF-α (p = 0.049). The blend suppressed VSV replication and significantly increased cytokine levels, with IFN-γ increasing by 98 pg/mL (p = 0.002), IL-1β rising by 233.0 pg/mL (p = 0.004), and TNF-α showing an increase of 2905 pg/mL (p = 0.002). These findings highlight the ELA blend's potential to alleviate URTI symptoms, modulate inflammatory and antiviral immune responses, and inhibit viral replication. Further investigations should aim to validate these findings through large-scale studies, and explore the ELA blend's long-term safety and efficacy in diverse populations. Additionally, research should investigate optimal dosing strategies and explore potential synergistic effects with conventional t

Echinacea purpurea (L.) Moench (EP), a medicinal plant native to North America, is now cultivated in various regions including Europe. With increasing popularity of Echinacea in Korea recently, a human clinical trial was conducted to evaluate immune-enhancing efficacy and safety of EP 60% ethanolic extract (EPE) in Koreans. Eighty volunteers were recruited for this randomized, double-blind, placebo-controlled clinical trial. They were randomly divided into two groups and given either a daily dose of 200 mg of EPE or a placebo. All participants underwent testing for Natural Killer (NK) cell cytotoxic activity, serum cytokine levels (IL-2, IL-6, IL-10, IL-12, IFN-γ, TNF-α), Wisconsin Upper Respiratory Symptom Survey-21 (WURSS-21), and Multidimensional Fatigue Scale (MFS) during this study to assess changes in outcomes. After 8 weeks of EPE consumption, a significant increase in NK cell cytotoxic activity compared to the placebo was observed. Additionally, serum cytokine levels of IL-2, IFN-γ, and TNF-α also significantly increased following EPE consumption. However, no significant changes were observed in WURSS-21 and MFS before and after EPE consumption. Throughout the 8-week study period, no adverse reactions were reported in relation to EPE consumption, and there were no clinically significant changes in diagnostic laboratory tests or vital signs in the EPE group. These results indicate that consumption of EPE could lead to immune improvement without any adverse effects. This clinical trial was the first to demonstrate beneficial effects of EPE consumption on immunity in Korean adults. © 2024 John Wiley & Sons Ltd.

Background and Objectives: Echinacea angustifolia and purpurea have known immunomodulatory effects which boost viral clearance, including HPV infection. However, evidence regarding the improvement due to Echinacea-based supplements of cervical HPV-related pathologies is still lacking. The aim of this study is to evaluate the efficacy of Echinacea supplementation on the remission of cervical low-grade squamous intraepithelial lesions (L-SIL). Materials and Methods: A single-blind 1:1:1 parallel randomized controlled trial was conducted at the Colposcopy Unit of a tertiary care referral center. Reproductive-aged women were allocated either to (a) an oral supplement based on Echinacea extracts plus vaginal hyaluronic acid-based soft gel capsules, (b) the Echinacea supplement alone, or (c) vaginal hyaluronic acid-based soft gel capsules alone for 3 months. The primary outcome was the regression of cervical intraepithelial neoplasia (CIN)-1 for each treatment arm at 3, 6 and 12 months after the diagnosis. Secondary outcomes included changes in the epithelialization, pap smear, colposcopic parameters, histological reports, and vaginal health indexes (VHI) in the study groups. Results: 153 women (52 for arm A, 50 for arm B and 51 for arm C) completed the follow-up and were included in the analysis. There were no significant differences in both primary and secondary outcomes for the three groups after 3 months. At the 6-month follow-up, the number of persistent CIN-1 diagnoses was significantly lower in arm A (15/51), rather than in arm B (23/48, p = 0.03) and C (27/49, p = 0.03). Similarly, the same effect was seen after 12 months for treatment A (5/51) relative to B (15/48, p = 0.03) and C (14/48, p = 0.03). Colposcopic, histological and vaginal parameters were all significantly improved at 6 and 12 months for arm A relative to B and C, while no beneficial effects were seen after 3 months. Conclusions: Echinacea extracts supplementation in women with L-SIL/CIN-1 significantly boosts HPV lesion clearance, reducing the overall amount of diagnosis, histological, colposcopic and vaginal parameters after 6 and 12 months. However, a limited sample size reduces the quality o

The objective of this study was to reveal the synergistic antibacterial activity and mechanism of Echinacea purpurea (L.) Moench crude extract (EE) and citric acid (CA) against Cronobacter sakazakii isolated from powdered infant formula (PIF). The minimum inhibitory concentration (MIC) of EE against C. sakazakii was determined, and then growth curve and time-kill analysis were used to screen the optimal antibacterial combination of 1 MIC of EE and CA. Changes in cell membrane potential, cell integrity, cell permeability, bacterial protein, DNA, and intracellular reactive oxygen species (ROS) levels, and cell morphology of C. sakazakii were used to reveal the synergistic inhibitory mechanism of EE and CA. The inactivation effect of EE in combination with CA against C. sakazakii on common contact surfaces was used to evaluate its efficacy as a natural disinfectant. The results showed that the MIC value of EE against C. sakazakii was 60 mg/mL, and the growth curve of C. sakazakii treated by 1 MIC of EE combined with CA (pH 3.0) was significantly inhibited compared with the control groups. The results of time-kill analysis showed that after combined treatment with 1 MIC of EE and CA (pH 3.0) for 30 min, approximately 8 log cfu/mL of C. sakazakii were inactivated. Cell membrane hyperpolarization, damaged cell membrane integrity, improved cell membrane permeability, decreased bacterial protein and DNA levels, increased and then decreased intracellular ROS contents, and deformed and ruptured cell morphology were found in C. sakazakii treated by EE combined with CA, and these phenomena were more pronounced than in C. sakazakii treated by EE or CA alone. When inoculated stainless steel, glass, ceramic, polystyrene, bamboo, and wood were sprayed with 1 MIC of EE combined with CA (pH 3.0) and after 15 min of treatment, approximately 5 log cfu/mL of C. sakazakii were inactivated. These findings suggest that EE combined with CA can effectively inactivate C. sakazakii isolated from PIF and can be used as a natural disinfectant to reduce the contamination of C. sakazakii in PIF production environments or households. The Authors. Published by Elsevier Inc. on behalf of the Ame

Preparations of Echinacea purpurea (E. purpurea) are widely used for the management of upper respiratory infections, influenza, and common cold, often in combination with other conventional drugs. However, the potential of phytochemical constituents of E. purpurea to cause herb-drug interactions via ABCB1 and ABCG2 efflux transporters remains elusive. The purpose of this study was to investigate the impact of E. purpurea-derived caffeic acid derivatives (cichoric acid and echinacoside) and tetraenes on the mRNA and protein expression levels as well as on transport activity of ABCB1 and ABCG2 in intestinal (Caco-2) and liver (HepG2) cell line models. The safety of these compounds was investigated by estimating EC20 values of cell viability assays in both cell lines. Regulation of ABCB1 and ABCG2 protein in these cell lines were analyzed after 24 h exposure to the compounds at 1, 10, and 50 μg/mL. Bidirectional transport of 0.5 μg/mL Hoechst 33342 and 5 μM rhodamine across Caco-2 monolayer and profiling for intracellular concentrations of the fluorophores in both cell lines were conducted to ascertain inhibition effects of the compounds. Cichoric acid showed no cytotoxic effect, while the EC20 values of tetraenes and echinacoside were 45.0 ± 3.0 and 52.0 ± 4.0 μg/mL in Caco-2 cells and 28.0 ± 4.3 and 62.0 ± 9.9 μg/mL in HepG2 cells, respectively. In general, the compounds showed heterogeneous induction of ABCB1 with the strongest 3.6 ± 1.2-fold increase observed for 10 μg/mL tetraenes in Caco-2 cells (p < 0.001). However, the compounds did not induce ABCG2. None of the phytocompounds inhibited significantly net flux of the fluorophores across Caco-2 monolayers. Overall, tetraenes moderately induced ABCB1 but not ABCG2 in Caco-2 and HepG2 cells while no compound significantly inhibited activity of these transporters at clinically relevant concentration to cause herb-drug interactions.

OBJECTIVE: Assessing adverse drug reactions (ADRs) is a proven method to estimate the safety of medicines. The ADRs to herbal medicines in Australia (and by inference, the safety of herbal medicines in Australia) remain unknown. This study examines spontaneous ADR cases to four of the most popular herbs in Australia from 2000 to 2015: echinacea (Echinacea purpurea), valerian (Valeriana officinalis), black cohosh (Actaea racemosa) and ginkgo (Ginkgo biloba). METHODS: ADRs of echinacea, valerian, black cohosh and ginkgo reported to the Australian Therapeutic Goods Administration (TGA) between 2000 and 2015 were obtained from the TGA database. Data were collated and analysed according to age, sex, severity, type of ADR and body system affected. Statistics were calculated using GraphPad Prism software. RESULTS: Most ADRs were mild or moderate. However, every herbal medicine was associated with life-threatening ADRs. In each life-threatening case, the herbal medicine was taken concomitantly with prescription medications. Black cohosh was associated with a significant number of severe ADRs (30.3% of the total), with 39.4% of these ADRs being associated with abnormal hepatic function, hepatitis or hepatotoxicity. CONCLUSION: This study highlights the lack of public awareness with regard to herb-drug interactions, since most of the severe ADRs involved a herb-drug interaction.

Comment in Pharmacol Res. 2019 Mar;141:609-610. doi: 10.1016/j.phrs.2019.01.033. Although several studies on pharmacokinetic and/or pharmacodynamic herb-drug interactions (HDI) have been conducted in healthy volunteers, there is large uncertainty on the validity of these studies. A qualitative review and a meta-analysis were performed to establish the clinical evidence of these interaction studies. Out of 4026 screened abstracts, 32 studies were included into the qualitative analysis. The meta-analysis was performed on eleven additional studies. St. John's wort (SJW) significantly decreased the AUC (p < 0.0001) and clearance (p = 0.007) of midazolam. Further subgroup analysis identified age to affect Cmax of midazolam (p < 0.01) in the presence of SJW. Echinacea purpurea (EP) significantly increased the clearance of midazolam (p = 0.01). Evidence of publication bias (p > 0.001) was shown on the effect of the herbal products o half-life of midazolam. Green tea (GT) showed significant 85% decrease in plasma concentration of nadolol. The study findings suggest that GT, SJW and EP perpetuate significant interactions with prescribed medications via CYP3A4 or OATP1A2. Our studies show that meta-analyses are important in the area of natural products to provide necessary information on their use in overall medication plans in order to avoid unintended interactions.

Echinacea purpurea, Echinacea angustifoli and Echinacea pallida are frequently used as medicinal plants. Besides asking for evidence on their efficacy, there is an increasing interest for safety data. This review systematically presents the available literature on drug interactions, contraindications, adverse events, duration of use, and safety of use in pregnant and nursing women, and assesses the safety profile of corresponding Echinacea preparations. It is noteworthy that all safety data reported are as product specific as the pharmacological or efficacy data are. In pharmacokinetic herb-drug interaction studies performed in vivo, no significant inhibitions of human CYP2D6 and CYP3A4 isoforms have been found after the administration of standardized E. purpurea preparations. However, contradictory results exist in studies using liver microsomes. Adverse events reported during clinical trials following administration of Echinacea spp. mono-preparations were generally mild and mostly without causality. Due to published long term studies with continuous ingestion of different Echinacea preparations up to 6 month with no reported toxicological concerns, Echinacea can be recommended also for long-term use. Moreover, the contraindications in cases of autoimmune diseases and immune-suppression are questionable, since lipophilic Echinacea preparations containing alkamides suppress cellular immune responses, and beneficial effects in autoimmunity were reported. The same applies for the use during pregnancy. Although there has been some impact reported on embryonic angiogenesis in mice, no association with an increased risk for major or minor malformations during organogenesis was found in a literature review. Altogether, the different evaluated Echinacea preparations are well-tolerated herbal medicines in the management in children and adults alike. Georg Thieme Verlag KG Stuttgart · New York.

1.This study investigated the mechanism underlying Echinacea-mediated induction of CYP1A2, CYP3A4 and MDR1 in terms of human pregnane X receptor (PXR) activation. 2.Crude extracts and fractions of Echinacea purpurea were tested for PXR activation in HepG2 cells by a reporter gene assay. Quantitative real-time PCR was carried out to determine their effects on CYP1A2 and CYP3A4 mRNA expressions. Capsules and fractions were risk ranked as high, intermediate and remote risk of drug-metabolizing enzymes induction based on EC50 values determined for respective CYPs. 3. Fractions F1, F2 and capsule (2660) strongly activated PXR with 5-, 4- and 3.5-fold increase in activity, respectively. Echinacea preparations potentiated up-regulation of CYP1A2, CYP3A4 and MDR1 via PXR activation. 4.Thus E. purpurea preparations cause herb-drug interaction by up-regulating CYP1A2, CYP3A4 and P-gp via PXR activation.

AIMS: The herbal medicine Echinacea purpurea (E. purpurea) has been shown to induce cytochrome P450 3A4 (CYP3A4) both in vitro and in humans. This study explored whether E. purpurea affects the pharmacokinetics of the CYP3A4 substrate docetaxel in cancer patients. METHODS: Ten evaluable cancer patients received docetaxel (135 mg, 60 min IV infusion) before intake of a commercially available E. purpurea extract (20 oral drops three times daily) and 3 weeks later after a 14 day supplementation period with E. purpurea. In both cycles, pharmacokinetic parameters of docetaxel were determined. RESULTS: Before and after supplementation with E. purpurea, the mean area under the plasma concentration-time curve of docetaxel was 3278 ± 1086 and 3480 ± 1285 ng ml(-1) h, respectively. This result was statistically not significant. Nonsignificant alterations were also observed for the elimination half-life (from 30.8 ± 19.7 to 25.6 ± 5.9 h, P = 0.56) and maximum plasma concentration of docetaxel (from 2224 ± 609 to 2097 ± 925 ng ml(-1) , P = 0.30). CONCLUSIONS: The multiple treatment of E. purpurea did not significantly alter the pharmacokinetics of docetaxel in this study. The applied E. purpurea product at the recommended dose may be combined safely with docetaxel in cancer patients. © 2013 The British Pharmacological Society.

The aim of this open-label, fixed-sequence study was to investigate the potential of the botanical supplement Echinacea purpurea to interact with etravirine, a nonnucleoside reverse transcriptase inhibitor of HIV. Fifteen HIV-infected patients receiving antiretroviral therapy with etravirine (400 mg once daily) for at least 4 weeks were included. E. purpurea root/extract-containing capsules were added to the antiretroviral treatment (500 mg every 8 h) for 14 days. Etravirine concentrations in plasma were determined by high-performance liquid chromatography immediately before and 1, 2, 4, 6, 8, 10, 12, and 24 h after a morning dose of etravirine on day 0 and etravirine plus E. purpurea on day 14. Individual etravirine pharmacokinetic parameters were calculated by noncompartmental analysis and compared between days 0 and 14 by means of the geometric mean ratio (GMR) and its 90% confidence interval (CI). The median age was 46 years (interquartile range, 41 to 50), and the median body weight was 76 kg (interquartile range, 68 to 92). Echinacea was well tolerated, and all participants completed the study. The GMR for etravirine coadministered with E. purpurea relative to etravirine alone was 1.07 (90% CI, 0.81 to 1.42) for the maximum concentration, 1.04 (90% CI, 0.79 to 1.38) for the area under the concentration-time curve from 0 to 24 h, and 1.04 (90% CI, 0.74 to 1.44) for the concentration at the end of the dosing interval. In conclusion, the coadministration of E. purpurea with etravirine was safe and well tolerated in HIV-infected patients; our data suggest that no dose adjustment for etravirine is necessary.

The extensive use of herbal drugs and their multiple components and modes of action suggests that they may also cause drug interactions by changing the activity of human cytochrome P450 enzymes. The purpose of the present review is to present the available data for the top 14 herbal drug sales in the U. S. Studies describing the effects of herbal drugs on phenotyping substrates for individual CYPs were identified by a comprehensive MEDLINE search. Drugs included Allium sativum (Liliaceae), Echinacea purpurea (Asteraceae), Serenoa repens (Arecaceae), Ginkgo biloba (Ginkgoaceae), Vaccinium macrocarpon (Ericaceae), Glycine max (Fabaceae), Panax ginseng (Araliaceae), Actea racemosa (Ranunculaceae), Hypericum perforatum (Hypericaceae), Silybum marianum (Asteraceae), Camellia sinensis (Theaceae), Valeriana officinalis (Valerianaceae), Piper methysticum (Piperaceae), and Hydrastis canadensis (Ranunculaceae) preparations. We identified 70 clinical studies in 69 publications. The majority of the herbal drugs appeared to have no clear effects on most of the CYPs examined. If there was an effect, there was mild inhibition in almost all cases, as seen with garlic or kava effects on CYP2E1 and with soybean components on CYP1A2. The most pronounced effects were induction of CYP3A and other CYPs by St. John's wort and the inhibitory effect of goldenseal on CYP3A and CYP2D6, both being borderline between mild and moderate in magnitude. With the exceptions of St.John's wort and goldenseal, the information currently available suggests that concomitant intake of the herbal drugs addressed here is not a major risk for drugs that are metabolized by CYPs. Georg Thieme Verlag KG Stuttgart · New York.

The aim of this open-label, fixed-sequence study was to investigate the potential of Echinacea purpurea, a commonly used botanical supplement, to interact with the boosted protease inhibitor darunavir-ritonavir. Fifteen HIV-infected patients receiving antiretroviral therapy including darunavir-ritonavir (600/100 mg twice daily) for at least 4 weeks were included. E. purpurea root extract capsules were added to the antiretroviral treatment (500 mg every 6 h) from days 1 to 14. Darunavir concentrations in plasma were determined by high-performance liquid chromatography immediately before and 1, 2, 4, 6, 8, 10, and 12 h after a morning dose of darunavir-ritonavir on days 0 (darunavir-ritonavir) and 14 (darunavir-ritonavir plus echinacea). Individual darunavir pharmacokinetic parameters were calculated by noncompartmental analysis and compared between days 0 and 14 with the geometric mean ratio (GMR) and its 90% confidence interval (CI). The median age was 49 (range, 43 to 67) years, and the body mass index was 24.2 (range, 18.7 to 27.5) kg/m(2). Echinacea was well tolerated, and all participants completed the study. The GMR for darunavir coadministered with echinacea relative to that for darunavir alone was 0.84 (90% CI, 0.63-1.12) for the concentration at the end of the dosing interval, 0.90 (90% CI, 0.74-1.10) for the area under the concentration-time curve from 0 to 12 h, and 0.98 (90% CI, 0.82-1.16) for the maximum concentration. In summary, coadministration of E. purpurea with darunavir-ritonavir was safe and well tolerated. Individual patients did show a decrease in darunavir concentrations, although this did not affect the overall darunavir or ritonavir pharmacokinetics. Although no dose adjustment is required, monitoring darunavir concentrations on an individual basis may give reassurance in this setting.

BACKGROUND: Gastrointestinal and respiratory diseases in calves and piglets lead to significant economic losses in livestock husbandry. A high morbidity has been reported for diarrhea (calves ≤ 35%; piglets ≤ 50%) and for respiratory diseases (calves ≤ 80%; piglets ≤ 40%). Despite a highly diverse etiology and pathophysiology of these diseases, treatment with antimicrobials is often the first-line therapy. Multi-antimicrobial resistance in pathogens results in international accordance to strengthen the research in novel treatment options. Medicinal plants bear a potential as alternative or additional treatment. Based on the versatile effects of their plant specific multi-component-compositions, medicinal plants can potentially act as 'multi-target drugs'. Regarding the plurality of medicinal plants, the aim of this systematic review was to identify potential medicinal plant species for prevention and treatment of gastrointestinal and respiratory diseases and for modulation of the immune system and inflammation in calves and piglets. RESULTS: Based on nine initial sources including standard textbooks and European ethnoveterinary studies, a total of 223 medicinal plant species related to the treatment of gastrointestinal and respiratory diseases was identified. A defined search strategy was established using the PRISMA statement to evaluate 30 medicinal plant species starting from 20'000 peer-reviewed articles published in the last 20 years (1994-2014). This strategy led to 418 references (257 in vitro, 84 in vivo and 77 clinical trials, thereof 48 clinical trials in veterinary medicine) to evaluate effects of medicinal plants and their efficacy in detail. The findings indicate that the most promising candidates for gastrointestinal diseases are Allium sativum L., Mentha x piperita L. and Salvia officinalis L.; for diseases of the respiratory tract Echinacea purpurea (L.) MOENCH, Thymus vulgaris L. and Althea officinalis L. were found most promising, and Echinacea purpurea (L.) MOENCH, Camellia sinensis (L.) KUNTZE, Glycyrrhiza glabra L. and Origanum vulgare L. were identified as best candidates for modulation of the immune system and inflammation. CONCLUSIONS: Se

BACKGROUND: Echinacea plant preparations (family Asteraceae) are widely used in Europe and North America for common colds. Most consumers and physicians are not aware that products available under the term Echinacea differ appreciably in their composition, mainly due to the use of variable plant material, extraction methods and the addition of other components. OBJECTIVES: To assess whether there is evidence that Echinacea preparations are effective and safe compared to placebo in the prevention and treatment of the common cold. SEARCH METHODS: We searched CENTRAL 2013, Issue 5, MEDLINE (1946 to May week 5, 2013), EMBASE (1991 to June 2013), CINAHL (1981 to June 2013), AMED (1985 to February 2012), LILACS (1981 to June 2013), Web of Science (1955 to June 2013), CAMBASE (no time limits), the Centre for Complementary Medicine Research (1988 to September 2007), WHO ICTRP and clinicaltrials.gov (last searched 5 June 2013), screened references and asked experts in the field about published and unpublished studies. SELECTION CRITERIA: Randomized controlled trials (RCTs) comparing mono-preparations of Echinacea with placebo. DATA COLLECTION AND ANALYSIS: At least two review authors independently assessed eligibility and trial quality and extracted data. The primary efficacy outcome was the number of individuals with at least one cold in prevention trials and the duration of colds in treatment trials. For all included trials the primary safety and acceptability outcome was the number of participants dropping out due to adverse events. We assessed trial quality using the Cochrane 'Risk of bias' tool. MAIN RESULTS: Twenty-four double-blind trials with 4631 participants including a total of 33 comparisons of Echinacea preparations and placebo met the inclusion criteria. A variety of different Echinacea preparations based on different species and parts of plant were used. Evidence from seven trials was available for preparations based on the aerial parts of Echinacea purpurea. Ten trials were considered to have a low risk of bias, six to have an unclear risk of bias and eight to have a high risk of bias. Ten trials with 13 comparisons investigated prevention and 15 trials w

BACKGROUND: Preparations of the plant Echinacea (family Compositae) are widely used in some European countries and in North America for common colds. Most consumers and physicians are not aware that products available under the term Echinacea differ appreciably in their composition, mainly due to the use of variable plant material, extraction methods and addition of other components. OBJECTIVES: The objective of this review was to assess whether there is evidence that Echinacea preparations are 1) more effective than no treatment; 2) more effective than placebo; 3) similarly effective to other treatments in A) the prevention and B) the treatment of the common cold. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2005); PubMed (1997 to April 2005), EMBASE (1998 to June 2005), AMED (to August 2005), Centre for Complementary Medicine Research (in Munich) (1988 to May 2005), contacted experts, and screened references of reviews. SELECTION CRITERIA: We included randomized controlled trials that compared mono-preparations of Echinacea with a placebo, no treatment, or another treatment for the prevention or treatment of common colds. Trials on combinations of Echinacea and other herbs were excluded. DATA COLLECTION AND ANALYSIS: For all studies, at least two authors independently assessed eligibility and trial quality, and extracted data. Outcomes of interest in prevention trials were: numbers of individuals with one or more colds, and severity and duration of colds; and in treatment trials: total symptom scores, nasal symptoms, and duration of colds. MAIN RESULTS: Sixteen trials including a total of 22 comparisons of an Echinacea preparation and a control group (19 with placebo, 2 with no treatment, 1 with another herbal preparation) met the inclusion criteria. All trials except one were described as double-blind. The majority had reasonable to good methodological quality. Three comparisons investigated prevention of colds and 19 comparisons tested treatment of colds. A variety of different Echinacea preparations were used. None of the three comparisons in the prevention trials showed an effect o