A preliminary investigation showed that polyoxyethylene emulsifiers contain substantial amounts of “free” polyethylene glycol. An improved method for determining these emulsifiers in foods is presented, in which the emulsifier is extracted with chloroform, “cleaned up” on an alumina column and analysed by thin-layer chromatography with a modified Dragendorff reagent to spray the chromatogram. The method is at least ±15 per cent. accurate down to an emulsifier level of 0·01 per cent. in fats and 0·001 per cent. in baked foods and food mixes. The detection of polyoxyethylene emulsifiers can be carried out at even lower levels.