The objective of this study was to evaluate whether certain foods and beverages that are high in sugar content or taste sweet are related to the prevalence and severity of the premenstrual syndrome. Specifically, we sought to evaluate whether consumption of "junk foods", chocolate, caffeine-free cola, fruit juices or alcoholic beverages might exert an effect on the premenstrual syndrome apart from any effects of daily consumption of beverages that are high in caffeine (caffeine-containing coffee, tea and colas). The study was based on 853 responses to a questionnaire probing menstrual and premenstrual health and certain daily dietary practices; it was mailed to female university students in Oregon. An analysis of the data revealed that the consumption of chocolate, but not of other junk foods, was related to the prevalence of the premenstrual syndrome among women with more severe premenstrual symptoms. Likewise, the consumption of alcoholic beverages (all alcoholic beverages and beer only) was related to the prevalence of the premenstrual syndrome among women with more severe symptoms, as were both fruit juice and caffeine-free soda. None of the associations was substantially altered when the daily consumption of beverages high in caffeine content was controlled for. Taken together, these data suggest that the consumption of foods and beverages that are high in sugar content or taste sweet is associated with prevalence of the premenstrual syndrome.