Devine, L F., D. P. Johnson, C. R. Hagerman, W. E. Pierce, S. L Rhode III and R. O. Peckinpaugh (Naval Medical Research Unit No. 4, Great Lakes, Illinois 60088). The effect of minocycline on meningococcal nasopharyngeal carrier state in Naval personnel. Amer J Epidem 93; 337–345, 1971.—Minocycline, a tetracycline analogue, was the subject of two studies. The first was a double-blind study in Naval recruit meningococcal carriers. Among 64 men who received 10 doses of minocycline (200 mg loading dose and 100 mg every 12 hours for 5 days), compared with 57 men who received placebo, there was an 84% reduction in carriers during treatment, and a relative reduction in carriers of 61% and 39%, respectively, at 3 and 11 days after treatment. In a second study, 29 men from Naval Service School served as controls, while 53 others received four 200-mg doses of minocycline at 12-hour intervals. Minocycline produced a relative reduction in nasopharyngeal carriers of meningococci of 67, 6%. No selection of drug-resistant strains was demonstrated during minocycline administration. However, over a third of individuals experienced minor side effects with this regimen, whereas, no side effects were noted in the first study. The clinical data obtained suggest that minocycline is moderately effective in the elimination of the meningococcal nasopharyngeal carrier state.