V aginitis is a common medical problem in women that is associated with substantial discomfort and frequent medical visits. Roughly 5 to 10 million office visits per year are attributed to vaginitis. 1 Research in recent years has increased our understanding of the disease process and its potential sequelae and resulted in improved diagnostic and treatment modalities. 2-6 Nevertheless, adequate diagnosis and treatment of vaginitis in the office setting often is problematic for practitioners. 2,5,7-9 Moreover, the availability of over-the-counter medications for fungal vaginitis has increased the likelihood that women will come to medical attention with partially or inadequately treated infections. 10 We will focus on the common infectious causes of vaginal discharge-yeast infection, bacterial vaginosis, and trichomonas infection, emphasizing new developments in diagnosis, associated complications, and treatment of these infections.The initial evaluation of vaginal discharge requires an understanding of physiologic vaginal discharge and what differentiates it from abnormal, pathologic discharge. Substances from the vulvar, sebaceous, sweat, Bartholin's and Skene's glands, as well as exfoliated cells, cervical mucus, and secretions of the endometrial cavity and fallopian tubes constitute the normal physiologic secretions of the vagina. These secretions pool in the posterior fornix and do not adhere to the vaginal walls. 11 The pH of normal vaginal secretions in women of childbearing age is between 3.8 and 4.5. The presence of sperm, blood, amniotic fluid, or cervical mucus raises the vaginal pH. 11 The amount and fluidity of the discharge can vary over the menstrual cycle. Cervical mucus becomes more fluid around ovulation, and women frequently mistake this change in consistency for an abnormal discharge. Stress increases the rate of vaginal desquamation and thus the amount of discharge, which patients can also mistake for a pathologic discharge. 12 Women generally do not have other symptoms if their discharge is physiologic.In contrast, a pathologic discharge adheres to the vaginal walls and is often accompanied by irritation, pruritus, odor, or urinary symptoms such as dysuria or frequency. 6 The discharge can be thick to watery and frothy, and white to yellow, gray, or green. 11 Causes of an abnormal discharge include infectious causes of vaginitis such as yeast infection, bacterial vaginosis, and trichomonas infection, as well as cervicitis and sexually transmitted diseases such as gonorrhea and chlamydia infection. Noninfectious etiologies include chemical irritants such