Nine patients with chronic exfoliative dermatitis were studied in order to delineate the problem of folate loss and absorption in this condition. Low serum folate activity was found in six patients. The folate content of exfoliated skin was compared with values obtained from normal skin, and a four- to six-fold increase was observed. At least 5μg to 20μg of folate activity were lost daily in the exfoliated skin from these patients. The gastrointestinal absorption of folic acid was normal in the three patients in which this was studied. It is shown that significantly large folate losses occur from skin sloughing in exfoliative dermatitis.