An account is presented of a patient who developed ileus, of greater or lesser severity, after each of seven operations (including two extra-abdominal and three Caesarean sections). During her most recent pregnancy, reviewed here, her plasma cholinesterase activity was found to be decreased and it remained low until at least the 6th day post-partum. However, as the normal activity had been gained by 6 weeks after delivery, the phenomenon had evidently been pregnancy-related. Despite receiving suxamethonium by infusion to completion of her Caesarean section, she did not show an abnormally prolonged response, although she did suffer considerable suxamethonium "after-pains". The question is posed of a possible relationship between the postoperative ileus, muscle pains and the decrease in cholinesterase activity.