The results displayed pulmonary ALDH2 mRNA and protein expressions were decreased in diabetic rats, while EtOH treatment increased ALDH2 expression and, meanwhile, decreased oxidative stress injury; it suggested that, in diabetes induced lung injury, the aggravation of oxidative stress may be derived from the decrease of pulmonary ALDH2 expression and improving pulmonary ALDH2 expression could be against the happening of hyperglycemia induced oxidative stress. This evidence concerns the gene ALDH2 and diabetes mellitus.