The effect of antipyretic treatment with acetaminophen on fetal status was examined in eight laboring women febrile with chorioamnionitis. After a fetal heart rate tracing and scalp blood gas level were obtained near maximum maternal fever, a 650-mg acetaminophen suppository was administered. If the temperature remained greater than 101 degrees F, the dose was repeated in one to two hours. The fetal heart rate tracing was analyzed again after the mother's fever was reduced by acetaminophen. All patients delivered within four hours of the first dose. Umbilical artery blood gases were obtained at delivery. Significant improvements in the bicarbonate concentration and base deficit were noted at the time of delivery as compared to the scalp gas at the height of the maternal fever. The fetal heart rate tracings at the height of the maternal fever, characterized by tachycardia, poor variability and late decelerations, changed to a normal heart rate pattern without decelerations when the mother's fever was reduced. Hence, in the laboring gravida with chorioamnionitis, reducing maternal fever with acetaminophen improves fetal status and thereby may reduce the probability of cesarean section for fetal distress.