OBJECTIVE: To describe severity of emotional and physical symptoms in a large diverse sample; to examine demographic, health status, and behavioral correlates of symptom severity; and to describe use of medications and alternative remedies for premenstrual symptoms. METHODS: A total of 1194 women, ages 21-45, selected from members of a large northern California health maintenance organization, completed daily ratings of symptom severity for two menstrual cycles. An empirically derived algorithm defined symptom severity groups as minimal (n = 186), moderate (n = 801), severe (n = 151), or premenstrual dysphoric disorder (n = 56). Symptom severity as a continuous variable was defined by the two-cycle mean symptom ratings in the luteal phase. Demographic, health status, and behavioral factors and use of treatments for premenstrual symptoms were assessed by self-report. RESULTS: Luteal phase symptom-specific ratings were generally significantly greater in the premenstrual dysphoric disorder group than in the other groups (P <.001). Symptom severity score increased with each comorbidity and decreased with each year of age. Symptom severity was also inversely associated with oral contraceptive use (emotional symptoms) and better perceived health (physical symptoms). Hispanics reported greater severity of symptoms, and Asians less, relative to whites. Use of herbal and nutritional supplements for premenstrual symptoms steadily increased from 10.8% in the minimal group to 30.4% in the premenstrual dysphoric disorder group (P <.01). CONCLUSION: The degree of premenstrual symptom severity varies in the population, is relatively constant within each woman over two consecutive cycles, particularly for emotional symptoms, and is influenced by age, race/ethnicity, and health status.