SHORT COMMUNICATIONS patch test to triphenyl phosphate, which is well recognised as an allergen (1-3). We cannot be certain whether the positive reaction to Lancromark LE 98 (R) is due to the small amount of triphenyl phosphite present or a true allergy to diphenyl iso-octyl phosphite.The clinical relevance of the positive reaction to phosphorus sesquisulphide is unclear. Although phosphorus sequisulphide and triphenyl phosphite both contain phosphorus, they do not seem to be closely chemically related.