Severe intractable atonic postpartum hemorrhage can be treated by either uterine packing or surgical techniques. However, certain prostaglandins possess properties of potential value for the control of postpartum uterine atony. Two hundred fifty micrograms 15-methyl prostaglandin F2&U0251;(15-methyl PGF2&U0251;) was given intramuscularly to 16 subjects for whom a uterine pack or operative management was the only other alternative. Fifteen patients responded satisfactorily following a mean of 1.75 injections (437.5 µg); only 1 patient required hysterectomy. The latter had a case of severe intrauterine infection. The incidence of side effects was very low. The use of intramuscularly administered 15-methyl PGF2&U0251;in uncontrollable atonic postpartum hemorrhage appears to be a valuable lifesaving medical tool in critical cases.