Randomised, double blind, placebo-controlled trial for testing the efficacy of a botanical formulation in reducing cold and flu symptoms

INTERVENTION: The 61 participants were randomised to the control (placebo) group or to the low dose or high dose treatment group of Resistex®. All three groups took their dietary supplement capsules just once a day. The low dose group took two 450 mg capsules (900 mg total); the high dose group took three 450 mg capsules (1350 mg); and the control group took three placebo (wheat starch) capsules. All were instructed to take their capsules as directed every day for the first four weeks. This segment was followed by a one week break during which no capsules were taken, and all subjects received a health check‐up by a physician. After the break, the subjects took their capsules as directed over a series of two‐weeks ?on?/one week ?off? periods for a total of 4.5 months. [Note: These breaks are a normal practice in TCM; they are incorporated to allow the immune system to take a periodic break from the up‐regulating effects of the herbs.] CONDITION: Common cold and flu ; Infections and Infestations ; Common cold and flu PRIMARY OUTCOME: The main outcome measures in this study were self‐reports of the frequency, duration, and severity of cold and flu symptoms as compared with the pre‐treatment assessment of the same variables. At the beginning of the study, all participants were queried about their cold and flu histories from the previous winter season (mid‐November to end of March).; ; Cold and flu symptoms included: headache associated with fever; nasal discharge; sore throat; sneezing; and chills or fever. To help subjects determine the frequency of colds or flu, the following criteria were established: ; 1. Family physician?s diagnosis of condition; 2. Simultaneous experiencing of two or more symptoms within a week; 3. Experiencing three or more symptoms without seeing a doctor. ; ; The questions were:; 1. How many times did you contract a cold or flu within the specified period?; 2. When you had a cold or flu, how many days did it usually take before the symptoms were alleviated?; 3. When you had a cold or flu, on a scale of one to five, how severe were the cold and flu symptoms? (1) barely noticeable, (2) mild, (3) moderate, (4) severe, (5) very severe; ; At the end of the study, the participants answered the same questions regarding the current winter season (mid‐November to end of March). SECONDARY OUTCOME: The subjects were asked whether they experienced any adverse effects/reactions. INCLUSION CRITERIA: 1. Aged 60 to 80 years old 2. Having a normal clinical chemistry profile (tested at baseline) 3. Physician clearance 4. Willingness to be randomised to the treatment or placebo groups and adhere to all aspects of the study protocol