To assess patterns of self-treatment and its effects on the duration of sexually transmitted disease (STD) symptoms before medical care. A cross-sectional interview survey in public STD clinics (7 U.S. cities). Patients, seeking treatment for STD symptoms or having a known infected sexual contact, reported self-treatment behaviors and symptom duration. Additional data were abstracted from medical charts. Self-treatment, primarily over-the-counter topical medications (54.8%), was reported by 21.8% of 2,508 symptomatic patients. Self-treaters were significantly more likely to be African-American (odds ratio [OR] = 1.8), female (OR = 1.7), over age 30 (OR = 1.3), report > 1 symptom (OR = 1.4), and report a genital lesion (OR = 2.1). Symptom duration was 2 days longer among self-treaters (p < 0.01). African-Americans (OR = 1.5), men (OR = 1.2), and self-treaters of symptoms other than genital lesions (OR = 1.4) had a significantly longer time from symptom onset to receiving medical care. Self-treatment is common among patients with STDs. Self-treatment of a genital lesion, unlike certain demographic factors and self-treatment of other STD symptoms, did not prolong the time to medical treatment.