In a study carried out in two hospitals in South Africa the authors identified 20 children suffering from hepatic veno-occlusive disease thought to be caused by the administration of traditional remedies. The predominant clinical presentation was ascites of various degrees and hepatomegaly. There was a high morbidity and mortality in the young infants, and in those cases who survived and were followed up the clinical pattern was one of progression to cirrhosis and portal hypertension. Pyrrolizidine alkaloid poisoning is one of the causes of the veno-occlusive disease. Therefore there is a need for objective confirmation of this. In four of our cases an on-admission urine specimen was available and in all of these a simple colorimetric screening test confirmed the presence of pyrrolizidine alkaloids. The other cases were admitted from peripheral hospitals and clinics and urine was not obtained until after 72 h, a time at which the levels of pyrrolizidines in urine were below the limit of sensitivity of the screening test. The screening method is helpful for the detection of acute ingestion of pyrrolizidines in large amounts, but is not sufficiently sensitive for the detection of chronic ingestion of smaller amounts. Nevertheless, in those patients who have hepatomegaly and ascites a positive finding of pyrrolizidines is important and may remove the necessity for expensive and invasive investigative measures.