We investigated the effects of an ethanol extract of potato peel on T helper cytokines production in cultured murine Peyer’s patch cells ex vivo. Oral administration of the 70% ethanol extract at 100 mg/kg/day significantly enhanced the production of the Th1 cytokine IL-2 in response to concanavalin A. A decrease in the production of the Th2 cytokine IL-4 and the Th17 cytokine IL-17 was observed. The production of the Treg cytokine IL-10 was not affected. These results suggest that the potato peel extract stimulates Th1 immune response.