Water-soluble, non-nitrogenous polysaccharides isolated from dermatophytes were tested for prophlogistic activity in the rat. Unlike the type II galactomannans, glucan, mannan and type I galactomannans from various dermatophyte species induce a dose-related swelling of the paw, which follows the same time-course as the oedema caused by dextran. The effect of the dermatophyte polysaccharides can also be antagonized by aminopyrine, tripelennamine, BOL and methysergide. The demonstrable prophlogistic activity of the dermatophyte polysaccharides studies is therefore presumably due to liberation of serotonin and histamine.