In our society today drug abuse is overcorninq. In several studies it has be found that 18 to 40 percent of patients are active drug abusers (alcohol, sedatives, stimulants cannabinoids, narcotics, and others). There are among them infectious complications, airways obstruction, parenchymal abnormalities, pulmonary edema, interstitial damage, bullous changes, atelectasis and vasculitis: some patients have abnormalities in control of ventilation, some other cases show several drug interactions. Physicians treating patients should be alert to possible drug interactions in drug abusers. The medical consequences of direct and indirect affects due to contaminants are extenses and are discussed. If the number of abusers increased, the varieties of complications involving the respiratory system surely will increase, and will be constitute in a major problem of public health.