Paracervical block using 20 ml of 0.25% bupivacaine alone, or with epinephrine 2.5 μg/ml, was given to 16 patients about to undergo elective cesarean section, who were then delivered between 5 and 30 minutes after the injection. Plasma bupivacaine concentrations were estimated in mother and baby. Bupivacaine alone produced maternal plasma concentrations double those after bupivacaine with epine-phrine. High concentrations of bupivacaine were not found in the neonates in this series. Direct intoxication of the fetus by local anesthetic agents is a possible cause of fetal brady-cardia and intrauterine death during paracervical block. Reasonable evidence is available to suggest that bupivacaine in a concentration of more than 0.25% should not be used for paracervical block in obstetrics.