In 63 patients with malabsorption syndromes, 16 with congenital biliary atresia (BA) and 47 with cystic fibrosis (CF), axonal dystrophy in the gracile nucleus (ADG) was studied. Of the 16 patients with BA, ADG of considerable severity was observed in all 10 over one year of age. Of the 47 patients with CF, it was observed in 32, 61 and 80% of the cases in the first, second, and third decades, respectively. Evidence is presented that there has been a substantial decrease in the incidence of ADG in CF patients in recent years and that the decreased incidence is attributable to vitamin E (Aquasol E) therapy. The beneficial effect of vitamin E supplementation in CF patients is proffered as strong evidence that ADG in BA and CF is related to vitamin E deficiency. The present study indicates that BA and CF patients require vitamin E supplementation to maintain a normal integrity of axons related to the gracile and perhaps other sensory nuclei. Critical neurological evaluation for possible dysfunction of the sensory nuclei in these patients with malabsorption syndromes is advised.