This review of the literature indicates that the incidence of psychiatric reactions to prescription and nonprescription respiratory drugs, such as decongestants, bronchodilators, expectorants, cough suppressants, and related agents, is low. When these reactions do occur they are most likely to appear in patients who are chronic users of these preparations, are overmedicated, or are chronic drug abusers in general. The authors found reports of toxicity to be in general scarce and poorly defined. A careful drug history with inquiry specifically directed at use of these agents is recommended when searching for possible causes of psychiatric reactions, in particular CNS stimulation, anxiety, and a nervous aspect to behavior.