Objective - A preliminary study to evaluate the usefulness of homeopathic treatment in the care of menstrual irregularities.Method - Patients were diagnosed at the first appointment according to menstrual cycle over the past year: Amenorrhea (AM), Oligo-amenorrhea (OL-AM), OL, Taking hormone replacement therapy (HRT). All patients were prescribed an individualised, global homeopathic treatment. The main outcomes were: time to resumption of periods, change of clinical diagnosis at the end of follow-up or after 2 years. The secondary outcomes were: menstrual regularity at the end of follow-up, compared to pre-treatment frequency; flow characteristics; clinical course of acute and chronic concomitant symptoms.Results - 18 consecutive cases of secondary amenorrhea (SA) and oligomenorrhea (OL) met the entry criteria. 8 women had SA, 2 were on HRT, 6 had OL-AM and 2 had OL. The average duration of considered follow-up was 21 months. The average time before the reappearance of menstruation was 58 days (s.d. 20) in the 8 women with SA at the time of the first appointment, for all cases 46 days (s.d. 42). Change of clinical diagnosis: 50% of women, who were diagnosed AM, recovered their ovulatory cycle (OV), whereas 12.5% remained amenorrheic; 33.3% of patients, who were initially OL-AM, showed an OV; 100% of oligomenorrheic and HRT patients recovered an OV. The average frequency of spontaneous cycles per year changes from 4.32 (s.d. 1.97) pre-treatment to 9.6 cycles per year at the end (s.d. 2.92). Four detailed case histories are reported.