A seven month-old boy had been suffering from recalcitrant pompholyx of both soles in spite of the treatment with corticosteroid ointment for three months. Because patch test of chromium was positive at 48 and 96 hr reading, we advised to his mother that the infant must avoid to touch and to take the chromium-containing goods. His lactating mother had been taking high amounts of chocolate and cocoa every day, both of which contain considerable amounts of chromium. The pompholyx disappeared within 2 weeks, after his mother stopped eating chocolate and cocoa. Oral provocation test with chocolate and cocoa to the patient's lactating mother resulted in the development of pompholyx in the baby within two days. We diagnosed the infant as systemic metal allergy to chromium which was possibly transferred from his mother's milk. This is the first report of systemic metal allergy which is provoked by mother's milk which is from the person who takes a lot of metal-containing foods.