2a 2b dihomo 15(S) 15 methyl PGF2 alpha methyl ester (dihomo 15 me PGF2 alpha) in intramuscular doses of 0.5 mg 8 hourly was used in 631 patients with abnormal intrauterine pregnancy comprising 282 cases of intrauterine fetal death, 233 cases of missed abortion, 34 and 82 cases respectively anencephalic and molar pregnancies. The study was carried out as a collaborative project between the University Departments of Obstetrics and Gynaecology in Singapore (Singapore), Medan (Indonesia) and Kuala Lumpur (Malaysia) during the period June 1974 and November 1979. Six hundred patients (95.1%) aborted or delivered in a mean time of 11.3 hours (S.D. +/- 7.0) with an average of 1.8 injections of the prostaglandin analogue per patient. Side effects included vomiting (23.6%; mean 0.45 episodes per patient), diarrhoea (44.4%; mean 1.00 episode per patient), cold and shivering (11.9%) and pyrexia (12.4%). One patient sustained a cervical laceration which did not require repair. There were no complications.