PIP: This group of researchers recently reported findings on the overall effect of Ascaris lumbricoides infection on human nutrition. On the basis of available data, it was suggested that intestinal malabsorption is a potential cause of nutritional impairment in children infected with Ascaris lumbricoides. The purpose of this discussion is to present additional data on the effect of Ascaris infection on small bowel function and structure in children. 5 children with heavy Ascaris infection without any evidence of clinical malnutrition were admitted to a metabolic unit. On admission, each child was placed on a constant diet consisting of 82-95 kcal and approximately 1 g protein/kg body weight/day. The amount of dietary fat varied from 55-60 g; the levels of vitamins and minerals in the diet were adjusted to meet the recommended dietary allowances. After an adjustment period of 4-6 days, fecal samples were collected during 2 periods of 4 days each for nitrogen and fat analysis. Peroral jejunal biopsies were obtained using an 8 mm Crosby-Kugler biopsy capsule. The samples were processed and stained according to standard techniques. The children then received deworming treatment consisting of 75 mg piperazine/kg body weight daily for 5 consecutive days. In 4 of 5 children there was reduced fecal nitrogen excretion; the mean reduction represented 6.5% of dietary nitrogen. Steatorrhea was present in 4 children; deworming resulted in a reduction of fecal fat from 9.9-2.3% of dietary fat. 3 children demonstrated an impairment in D-xylose excretion. It returned to normal following deworming in only 1 child. The jejunal morphology was found to be abnormal in all children. In each case a significant improvement was noted soon after deworming. The study results strongly suggest that there is a cause and effect relationship between Ascaris infection and intestinal lesions in children.