The ability of microorganisms present in titers of over 10(5)/ml in the vaginal or cervical secretions to inhibit growth of N. gonorrhoeae in vitro was tested. Study of a strain of N. gonorrhoeae against 77 microorganisms demonstrated that most strans of S. epidermidis, S. aureus and the one "Gaffkya anaerobia" interfered with the growth of the N. gonorrhoeae. A minority of strains of S. viridans, Neisseria, Candida and Bifidobacterium demonstrated interference. No strains of enterococcus, diptheroids, aerobic Lactobacillus, Peptostreptococcus, Peptococcus, anaerobic Lactobacillus or Veillonella demonstrated interference.