Human gastrectomy specimens, including 48 carcinomas and 25 selected benign cases showing extensive intestinal metaplasia (IM), were examined in detail histologically and histochemically. IM was classified into complete (type I), incomplete without sulphomucins (type IIA) and incomplete with sulphomucins (type IIB). Type IIB was associated with 'intestinal' but not 'diffuse' cancers (P less than 0.01) or benign lesions (P less than 0.01). The mucin profiles of IIB IM were similar to 'intestinal' cancers with sulphomucins predominating over N-acetylsialomucins. O-acetylsialomucins were not seen in IIB IM or tumours but were observed in complete or type I IM. These findings suggest a histogenic link between incomplete IM secreting sulphomucins (or 'colonic' metaplasia) and 'intestinal' cancers of the human stomach.