Flagellate erythema secondary to shiitake mushroom (Lentinus edodes) ingestion is a condition that was first documented in 1977 by Nakamura and has been reported in Japan, Europe, and the United States. Herein, we present two cases of flagellate erythema after a couple ate a meal containing shiitake mushrooms at a chain restaurant. We hypothesize that this condition may not be as rare or as dependent on volume of exposure as previously suggested, considering that two genetically unrelated individuals simultaneously developed the eruption after minimal exposure.