Quercetin and butylated hydroxytoluene (BHT) were given at a 1% dietary concentration to male Syrian golden hamsters exposed to cigarette smoke for a period of 13 weeks to study effects of the antioxidants on smoke inhalation toxicity. In comparison with the smoke-exposed controls, the quercetin-supplemented hamsters showed slightly improved body weight gain and food efficiency and a significant inhibition of thickening of the laryngeal mucosa, whereas BHT treatment resulted in marked growth retardation and significant depletion of liver vitamin A level. These results indicate that quercetin but not BHT may have some ameliorative effects on the biological damage elicited by cigarette smoke.