Dietary restriction improves declining physiologic functions, prevents or lessens the severity of neoplasms and autoimmune diseases, and attenuates various inflammatory reactions. In the present study, we compared the effect on allergic dermatitis from repeated short-term fasting (every 3 days), and from moderate dietary restriction receiving 60% of the amount of food consumed by an ad libitum feeding group. In addition, we attempted to verify the involvement of corticosteroids and oxidative stress during nutritional deprivation. The overall food intake in mice undergoing moderate dietary restriction was less than that in mice undergoing repeated fasting. Nonetheless, moderate dietary restriction and repeated fasting showed similar suppressive effects on dermatitis. Furthermore, both the restricted-diet and fasted mice showed less oxidative stress than the mice fed ad libitum. In RU486 (a glucocorticoid receptor antagonist)-injected mice, no suppressive effect of fasting on dermatitis was seen. In conclusion, repeated fasting and moderate dietary restriction suppressed dermatitis in similar ways. Hypercorticism and reduced oxidative stress is associated with the suppression of dermatitis.