Using brilliant cresyl blue, Nile blue, neutral red, azur Ⅱ and eosin, the author has observed the influence of saponin, Thyradin (powder of dried thyroid gland), progesterone, cortisone, Kontomin (chlorpromazine) and Megabion (17α-methyl-androstene-3β-17β-diol) on the permeability of dyes to granulocytes. Thyradin and Megabion acted as to accelerate the permeability of both acidic and basic dyes, while cortisone and Kontomin restrained the invasion of these dyes info cells. Saponin promoted the invasion of basic dyes and restrained the invasion of eosin. Progesterone showed a depressing effect on the invasion of basic dyes. From these results the mechanism of the pharmacological action of these drugs was breafly discussed.