Clinical trial, with positive findings, on 19 women with premenstrual syndrome and attending a gynaecology outpatient clinic in Israel. Approximately half of the women were randomly allocated to receive homeopathic medicine, and the others received dummy medicine (placebo); they were not told which treatment group they were in. After 3 months, relief of symptoms was reported by 90% of the women who received homeopathy compared to 37% of women who received placebo.