Altered frequency of the menstrual cycle accompanied by pain are manifestations of functional anomalies of the female reproductive system. These symptoms require prompt and accurate diagnosis and therapy to prevent a chronic condition that can seriously disturb the adolescent's psychic well being. The most common anomalies of the menstrual cycle and the causes of altered cycle frequency are outlined, as are useful criteria for diagnosing premenstrual syndrome dysmenorrhea and for distinguishing the causes and alterations in frequency and amount of menstrual discharge from other disturbances, including amenorrhea and abnormal uterine bleeding. The treatment of dysmenorrhea and quantitative alterations of the menstrual cycle is the focus of this article.