Trial reportAnnals of allergy, asthma & immunology : official publication of the American College of Allergy, Asthma, & Immunology2008
Effects of echinacea on the frequency of upper respiratory tract symptoms: a randomized, double-blind, placebo-controlled trial.
Trial report in Annals of allergy, asthma & immunology : official publication of the American College of Allergy, Asthma, & Immunology, 2008. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 10 papers, 3 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
10 citing papers in PubMed, 3 syntheses or guidelines pooled it, 26 citations in OpenAlex.
- Select Dietary Supplement Ingredients for Preserving and Protecting the Immune System in Healthy Individuals: A Systematic Review.Nutrients · 2022Pooled it
- Medicinal plants--prophylactic and therapeutic options for gastrointestinal and respiratory diseases in calves and piglets? A systematic review.BMC veterinary research · 2016Pooled it
- Echinacea for preventing and treating the common cold.The Cochrane database of systematic reviews · 2014Pooled it
- Randomized, double-blind, placebo-controlled clinical trial to assess the safety and effectiveness of a novel dual-action oral topical formulation against upper respiratory infections.BMC infectious diseases · 2017Trial
- A Review of the Properties of Clinically Evaluated Plant-Derived Agents in the Treatment of Respiratory Infections.Nutrients · 2026Review
- Echinacea Reduces Antibiotics by Preventing Respiratory Infections: A Meta-Analysis (ERA-PRIMA).Antibiotics (Basel, Switzerland) · 2024Review
- The Importance of Reference Materials and Method Validation for Advancing Research on the Health Effects of Dietary Supplements and Other Natural Products.Frontiers in nutrition · 2021Review
- The effect ofAdvances in integrative medicine · 2020Article
- Echinacea and elderberry-should they be used against upper respiratory tract infections during pregnancy?Frontiers in pharmacology · 2014Review
- Determination of major phenolic compounds in Echinacea spp. raw materials and finished products by high-performance liquid chromatography with ultraviolet detection: single-laboratory validation matrix extension.Journal of AOAC InternationalArticle
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors at 1 institution in 1 country.
Funding
Abstract
backgroundUpper respiratory tract infection symptoms are a common cause of morbidity. Herbal preparations of the plant Echinacea purpurea have immune-enhancing properties.
objectiveTo compare the frequency of upper respiratory tract symptoms in individuals receiving E. purpurea capsules and those receiving placebo to evaluate the preventive efficacy of echinacea.
methodsIn a randomized, double-blind clinical trial, 90 volunteers recruited from hospital personnel were randomly assigned to receive 3 capsules twice daily of either placebo (parsley) or E. purpurea for 8 weeks during the winter months. Upper respiratory tract symptoms were reported weekly during this period.
resultsFifty-eight individuals were included in the final data analysis: 28 in the echinacea group and 30 in the placebo group. Individuals in the echinacea group reported 9 sick days per person during the 8-week period, whereas the placebo group reported 14 sick days (z = -0.42; P = .67). Mild adverse effects were noted by 8% of the echinacea group and 7% of the placebo group (P = .24).
conclusionProphylactic treatment with commercially available E. purpurea capsules did not significantly alter the frequency of upper respiratory tract symptoms compared with placebo use.
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What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.