Acute intermittent porphyria is an unusual syndrome that may be very difficult to differentiate from acute intraabdominal processes. Diagnosis requires the documentation of increased urinary porphobilinogen. Failure to perform appropriate tests early in the attack may necessitate diagnostic laparotomy to rule out intraabdominal catastrophies. Once the diagnosis has been made, treatment with intravenous dextrose aborts most acute episodes. Patients should avoid such triggering factors as fasting and certain drugs. Screening of family members is important to identify latent carriers.