We analyzed the relation between cigarette smoking, alcohol consumption, and risk of dysmenorrhea using data from a case-control study in Milan, Italy. With never-smokers as the reference category, the relative risk (RR) of dysmenorrhea was 1.9 [95% confidence interval (CI) = 0.9-4.4] for women smoking 10-30 cigarettes per day. The risk of dysmenorrhea increased with duration of smoking in women who smoked for less than 10 years (RR = 1.3, 95% CI = 0.6-2.6) and in those who smoked for 10-20 years (RR = 2.8, 95% CI = 1.3-6.2). In comparison with teetotalers, the age-adjusted RR of dysmenorrhea was 0.8 (95% CI = 0.4-1.5) for alcohol drinkers.