Smoking and second-hand smoke strongly increase incidence of diabetes and probability for its complications. Smoking cessation can lead to weight gain and increased diabetes risk; however, it decreases cardiovascular and total mortality. A basal diagnostics (Fagerström Test, exhaled CO) is the basis for successful smoking cessation. Supporting medication include Varenicline, Nicotine Replacement Therapy and Bupropion. Socio-economic as well as psychological factors play an important role for smoking and smoking cessation. Heated tobacco products (like the E‑cigarette) are no healthy alternative to cigarettes and are associated with increased morbidity and mortality.Moderate consumption of alcohol possibly decreases risk for diabetes and cardiovascular diseases. Selection bias and underreporting in studies maybe contribute to a too optimistic view. On the other hand, alcohol increases in a dose dependant fashion excess morbidity and disability adjusted life years, especially by cancer, liver diseases and infections.