The adsorption from solution onto griseofulvin powder of a series of non‐ionic detergents of the polyoxyethylene glycol mono alkyl ether type is described. Results are also given for polyethylene glycol 400 and a new detergent, pentaerythritol mono‐n‐octyl ether, whose synthesis and purification is reported. The effect of temperature on the adsorption is studied and possible explanations of the variation of adsorption with temperature are based on the orientation of the molecules at the interface; this is deduced from measured molecular areas.