Use of spiculisporic acid and/or a salt thereof as antidandruff agent and cosmetic treatment process employing same. The present invention relates to the cosmetic use especially for hair of spiculisporic acid and/or a salt thereof as anti dandruff agent. The invention also relates to a cosmetic treatment process intended for eliminating dandruff and/or for reducing the amount thereof comprising the application to the hair and/or the scalp of spiculisporic acid and/or a salt thereof or of a cosmetic composition comprising it/them.