We analyze consumers’ demand for mint gum accounting for product heterogeneity and unobservable, to the econometrician, flavor quality. We use the control function (CF) approach in the context of a discrete choice logit model in an oligopolistic framework, where price-setting firms endogenously determine prices. We found that when using the control function approach, demand estimators are improved by reducing potential biases generated by endogeneity. We found that gum is price inelastic with respect to price and quality. Implications for the mint oil industry in the Pacific Northwest are cited.