A critical review of the literature on amine composition and relevant case reports provides rational guidelines for diet planning and counseling of patients on monoamine oxidase inhibitor (MAOI) drug regimens. Small amounts of normally harmless pressor amines in foods can lead to a hypertensive crisis, which is often termed the "cheese reaction." Initial recognition of the problem led to reduced usage of MAOIs and overzealous food restrictions. Recently, confidence in handling such reactions and in MAOI usage has increased. MAOIs treat anxiety and depression by supposedly inhibiting the inactivation of neurotransmitters. A side effect is the concurrent failure to inactivate the potent vasopressor amine, tyramine. Consumption of 6 mg of tyramine may produce a mild crisis whereas 10 to 25 mg may produce severe headaches with intracranial hemorrhage and its sequelae. Any food rich in aromatic amino acids can become high in tyramine if aging, contamination, prolonged storage, or spoilage occurs. Tables are presented listing the current MAOI drugs; the pressor amines; the tyramine content of various cheeses; and foods to avoid, foods to use with caution, and foods that are not restricted. Rational guidelines for dietary counseling in MAOI usage include: keep tyramine intake below 5 mg, begin diet counseling before drug therapy, monitor patient compliance, recommend preparation and consumption of only fresh foods, and continue the diet four weeks beyond drug therapy.