A case report of a hypertensive crisis resulting from the ingestion of tap beer in a patient on an irreversible monamine oxidase inhibitor (MAOI; phenelzine) stimulated the investigation of different kinds of beer for tyramine concentration. The objective was to determine the tyramine concentration in tap and bottled beers. A total of 98 beer samples (79 different brands of beer) were analyzed by high-performance liquid chromatography for tyramine. Of these 98 beers, 49 were bottled or canned beers and 49 were beers on tap. All of the bottled beers analyzed had safe tyramine concentrations (≤10 mg/liter; range, 0 to 3.16 mg/liter) and, thus, do not require restriction in patients receiving MAOIs. Therefore, the consumption of canned or bottled beer, including dealcoholized beer, in moderation (fewer than four bottles or cans; 1.5 liters within a 4-hour period) appears to be safe and does not require restriction in patients receiving MAOIs. Only 4 of 98 beer samples studied were found to have a dangerous (>10 mg/liter) tyramine concentration, one of which was the index beer. The tyramine concentration in these four beers ranged from 26.34 to 112.91 mg/liter. All four of these beers were tap beers produced by bottom fermentation (lagers) and brewed by a secondary fermentation process. Although we did not find any visible bacterial growth in the tap beers with high tyramine content, this finding does not preclude the possibility that bacterial contamination, bacterial growth, production of tyramine, and eventually bacterial death occurred at some earlier time. Therefore, to err on the side of caution, it is recommended that patients on irreversible MAOIs avoid beers on tap.