The relationship between tobacco, alcohol and the risk of oesophageal adenocarcinoma in Barrett's oesophagus was evaluated in an endoscopy-clinic-based case-control study of 30 histologically confirmed cases of adenocarcinoma and 140 controls with Barrett's oesophagus but no evidence of malignant lesions. Among the cases, 18 (60%) were non-smokers and 14 (47%) non-drinkers, the corresponding proportions in the controls being 52% and 44%. Thus, there was no apparent relation between tobacco, alcohol and the risk of adenocarcinoma of the oesophagus, the age- and sex-adjusted point estimates being 1.0 for moderate and 0.9 for heavy smokers, 0.7 and 1.5 respectively for moderate and heavy drinkers. Upper 95% confidence limits were 1.6 for ever-use of tobacco and 1.9 for ever alcohol drinking. The findings of this study, although based on a limited number of cases, indicate that alcohol and tobacco are unlikely to play a major role in the aetiology of adenocarcinoma in Barrett's oesophagus.