Clinical Update: Echinacea purpurea Liquid Extract Effectively Treats the Common Cold in Adults

摘要

In a randomized, double-blind, placebo-controlled trial, 282 males and females aged 18-65 years with a history of two or more colds in the previous year, but otherwise in good health, were recruited to study the efficacy of a standardized Echinacea purpurea liquid extract (40% alcohol) in treating the common cold. Manufactured by Natural Factors, Burnaby, British Columbia, Canada, the extract Echinilin* is made from flowering tops of freshly harvested plants and is standardized to contain alkamides/cichoric acid/polysaccharides at concentrations of 0.25/2.5/25.5 mg/ml, respectively. Subjects were randomized to receive either echi-nacea extract or placebo for 7 days and were instructed to begin treatment at the onset of the first symptom related to a common cold. Treatment consisted of 10 doses the first day and 4 doses per day for the next 6 days. A dose was 4 ml of the echinacea extract or placebo diluted in a half glass of water.