Small bowel morphology in British Indian and Afro-Caribbean subjects: evidence of tropical enteropathy. Distal duodenal biopsy specimens taken from 30 white, 35 Indian, and 20 Afro-Caribbean residents of West Birmingham during routine endoscopy for dyspepsia, were assessed by dissecting microscopy and morphometry. Finger-shaped villi were significantly less frequent in the Indian and Afro-Caribbean subjects than in the white subjects when assessed by dissecting microscopy (p less than 0.005), and both immigrant groups had decreased mucosal thickness (p less than 0.01), villous height (p less than 0.001), villous:crypt ratios (p less than 0.01) and enterocyte height (p less than 0.05) compared with the white group. In the Indian subjects, villous height and villous:crypt ratios correlated significantly with the time since the last visit to the Indian subcontinent (p less than 0.005). Serum alkaline phosphatase values were significantly higher in the Indian subjects compared with the whites (p less than 0.02), and serum globulins were increased in both the Afro-Caribbean and Indian subjects (p less than 0.01). There were no correlations between morphometric indices and body habitus or biochemical or haematological indices and the long term effect of the morphological changes is not clear. 