In the treatment of obstructive pulmonary emphysema and bronchial asthma it is important to avoid certain procedures that may further handicap respiratory mechanisms already on the verge of exhaustion. Persistent respiratory insufficiency is in itself a dangerous state. Drugs that reduce anxiety, relieve insomnia, and suppress coughing may be physiological luxuries which the patient cannot afford; they must be chosen with care and given in small or average, rather than large, doses. Profound narcosis with any drug is dangerous in severe asthma or in emphysema complicated by respiratory infection. For cyanosis the rational therapy is oxygen, but patients receiving it must be watched closely for signs of carbon dioxide narcosis. Violent reactions to penicillin or even to such simple drugs as aspirin are especially likely in patients with asthma and may occur in many patients with emphysema. Patients with these diseases urgently need treatment directed at the underlying condition.