Vaginal discharge is a common complaint, the cause of which can be diagnosed on the basis of the distinguishing characteristics of the fluid itself, the course and symptoms of the infection, and the results of a few simple office laboratory tests. Accurate diagnosis is important because treatment can then be selected specifically rather than empirically. Optimal treatment differs with each of the four major causative agents: Candida, Gardnerella, Trichomonas, and Chlamydia. Prompt eradication of the infection promotes patient and public health.