INTRODUCTION: Alcohol intake measured at one point in time is a strong predictor for later development of cancer of the oral cavity, pharynx, larynx and esophagus. In this prospective cohort study, we examined whether changes in individual alcohol intake resulted in subsequent altered risk of these cancers. MATERIAL AND METHODS: In the Copenhagen City Heart Study we assessed alcohol intake among 4 896 men and 6 239 women who participated at both the first (1976-1978) and second (1981-1983) examination of the study. Alcohol intake changes on risk of upper digestive tract cancer 1981-2002 were examined by a Cox model adjusted for potential confounders. RESULTS: Despite a small number of cases (n = 105), alcohol intake increase > 14 drinks/week was associated with significantly elevated risk (hazard ratio = 2.5; 95% confidence interval, 1.1-5.3), while suggestively decreased risk was observed for persons lowering alcohol intake > 7 drinks/week (0.5; 0.1-2.5). The trend test was highly significant (p < 0.0001). CONCLUSIONS: These findings support public health messages of not increasing alcohol intake and lowering consumption among people with high alcohol intake.