J Altern Complement Med. 2000 Aug; 6(4): 327-34.

The efficacy of echinacea compound herbal tea preparation on the severity and duration of upper respiratory and flu symptoms: a randomized, double-blind placebo-controlled study.

Lindenmuth GF, Lindenmuth EB.

Rest Haven-York, York College of Pennsylvania, USA.

OBJECTIVES: The aim of this study was to determine the efficacy of an echinacea compound herbal tea preparation (Echinacea Plus) given at early onset of cold or flu symptoms in a random assignment double-blind placebo-controlled study. DESIGN AND SUBJECTS: A total of 95 subjects with early symptoms of cold or flu (runny nose, scratchy throat, fever) were randomly assigned to receive Echinacea Plus tea five to six cups per day titrating to 1 over 5 days or placebo in a double-blind situation. Each participant completed a questionnaire 14 days after beginning the program. The efficacy, number of days the symptoms lasted, and number of days for change were measured with a self scoring questionnaire. RESULTS: The study period was 90 days (January 1, 1999 to March 30, 1999). There was a significant difference between the experimental group (Echinacea Plus) and control group (placebo) for all 3 questions measured: p < 0.001. There were no negative effects reported by any of the subjects in either group. CONCLUSIONS: Treatment with Echinacea Plus tea at early onset of cold or flu symptoms was effective for relieving these symptoms in a shorter period of time than a placebo.