The aqueous solution of folic acid has a feeble white blue fluorescence which is markedly intensified by an addition 10^<-5> solution of KMnO_4 and distinctly decreases its intensity changing to yellowish green by an addition of HCl. Utilizing these characters as a histochemical detection method of folic acid in the organs of rats was established. The normal rats were orally and subcutaneously given by folic acid, and it was observed that the folic acid is absorbed from the intestine and stomach, and excreted from bile ducts, stomach and glandular cells of the intestine. The absorbed folic acid is mostly transported into liver cells. In the liver cells the vitamin is found abundantly in cytoplasm and scarcely in nucelei.