Echinacea for Treating the Common Cold

Abstract

Background Echinacea is widely used to treat common cold. Objective To assess potential benefits of echinacea as common cold treatment. Design Randomized controlled trial with four parallel groups: 1) no pills, 2) placebo pills (blinded), 3) echinacea pills (blinded), or 4) echinacea pills (open-label). (NCT00065715) Setting Community-based trial. Participants People aged 12 to 80 years with new onset common cold. Interventions Extracts of Echinacea purpurea and E. angustifolia root were used to make tablets standardized to alkamide content. Indistinguishable placebo tablets contained only inert ingredients. Measurements The primary outcome was area-under-the-curve global severity, with severity assessed twice daily by self report on the Wisconsin Upper Respiratory Symptom Survey (WURSS-21). Secondary outcomes included interleukin-8 and neutrophil count from nasal wash assessed at intake and two days later. Results Of 719 enrolled, 713 completed the protocol. Participants were 64% female and 88% white, with mean age 33.7 years. Mean global severity was 236 and 258 for blinded and unblinded echinacea, 264 for blinded placebo, and 286 for those without pills. Contrasting the two blinded groups yields a 28 point (95% CI = −69 to 13) trend toward benefit for echinacea (p=0.089). Mean illness duration for the blinded and unblinded echinacea groups was 6.34 and 6.76 days, respectively, compared to 6.87 days for blinded placebo and 7.03 for no pills. Contrasting blinded groups yields a 0.53 day (95% CI = −1.25 to 0.19) trend toward benefit (p = 0.075). Median change interleukin-8 (pg/mL) and neutrophil cell count were: no pills (30, 1), blinded placebo (39, 1), blinded echinacea (58, 2), and open-label echinacea (70, 1), also not statistically significant. Limitations Higher-than-expected variability limited power to detect small-but-potentially-important benefits. Conclusions The observed shorter illness duration and lower severity seen in the echinacea groups were not statistically significant. These results do not support the ability of this dose of this echinacea formulation to substantively change the course of the common cold.

Placebo Effects and the Common Cold: A Randomized Controlled Trial

“…We chose a design that would assess 2 kinds of pill-related placebo effects (no pill vs blinded to placebo, and blinded to vs open-label treatment) and would also provide evidence regarding potential effects of physician-patient interaction. Our review of the relevant literature, 33 detailed methods, 34 and results related to echinacea 35 and physician-patient interaction 36 are available elsewhere.…”

“…Echinacea tablets included root extracts of Echinacea purpurea and E angustifolia. 35 Placebo and echinacea tablets measured 9 mm by 19 mm and were covered by reddish brown digestible coatings. Investigators and colleagues found it impossible to distinguish between the placebo and echinacea pills in terms of appearance, smell, or taste.…”

Validation of the Nasal Mucus Index, a Novel Measurement of Acute Respiratory Infection Severity

“…3,[8][9][10] This study was approved by the University of Wisconsin-Madison Health Sciences Institutional Review Board, and informed consent was obtained from all the subjects. All human research guidelines of the United States Department of Health and Human Services and of the University of Wisconsin were followed.…”

“…Detailed methods and results are available elsewhere. 3,[8][9][10] Objective ARI Monitoring Nasal lavage was collected twice during the study, once at enrollment (day 1), and then again 2 days later (day 3). The NMI test is conducted by instilling a 5-mL aliquot of sterile isotonic medium into each nostril, followed by expression into a sterile container.…”

Complementary and Alternative Medicine (CAM) Utilization by Howard University (HU) First Year Pharmacy Students: Survey and Review of Most Commonly Used Herbs

“…Echinacea is one of the most widely used herbal products in the United States (20). There are nine known different species of Echinacea, and they contain different chemicals, such as glycoproteins, polysaccharides, alkamides, and volatile oils (20).…”