1. The absorption of orally administered pteroylmonoglutamate and pteroyltetraglutamate, measured as peak rise in serum folate levels, was examined in normal volunteers and in epileptic patients on anticonvulsant drugs.
2. Although the fasting serum folate levels were low in the patients, they absorbed the two folate forms as well as the volunteers did and there was no difference between the absorption of pteroylmonoglutamate and pteroyltetraglutamate.
3. The findings indicate that the folate deficiency, caused by anticonvulsant drugs is not due to interference with the intestinal conjugase or the mechanism of absorption in itself.