OBJECTIVE: To investigate the growth of interest, if any, in complementary or alternative medicine by the professional scientific community from the number of MEDLINE-listed and clinical trial-type articles for January 1, 1966, through December 31, 1996. METHODS: Systematic literature searches of the MEDLINE database, using the expanded terms "alternative medicine," "traditional medicine," "acupuncture," "homeopathy," and "chiropractic," were conducted in January 1998 to evaluate the number of all articles. The number of clinical trial-type articles on the above was obtained by conducting searches for those indexed as 1 or more of the following publication types: clinical trial; clinical trial phase 1, 2, 3, or 4; controlled clinical trial; metaanalysis; randomized controlled trial; and limited to "human" trials only. RESULTS: Articles indexed as alternative medicine formed a small proportion (0.4%) of the total number of MEDLINE-listed articles throughout the period studied. From 1966 through 1996, the total number of articles listed in MEDLINE rose significantly to a peak of 400000 additions per annum in 1996 (r = 0.97; P