The uptake and translocation of griseofulvin from water culture by broad bean and tomato has been studied; observations were also made on its decay in broad bean. In most cases griseofulvin was determined by bioassay. Where possible the bioassay was checked by chemical estimations and was found to be adequate. The amount of griseofulvin taken up by the broad bean was proportional to the volume of water transpired for any single concentration of the treating solution and the decay was exponentially related to the time of exposure in the tissues. The accumulation of griseofulvin in the tissue had, therefore, an exponential component but within the limits of error there was constant relationship between accumulation and transpiration over the time periods used in the trials. The rate of accumulation in tomato was also constant. The amount of griseofulvin accumulated by both bean and tomato after a definite time was a linear function of the concentration of the treating solution. There were two processes involved in the uptake of griseofulvin by the broad bean: (a) an initial rapid entry into the roots which was inhibited by sodium azide and dinitrophenol at concentrations which did not reduce transpiration; and (b) a prolonged uptake linearly related to transpiration which was not affected by these concentrations of the inhibitors.