Cinchocaine (dibucaine) is used in the form of ointments or injection solutions as a local anaesthetic. Its base is soluble in diethyl ether; its hydrochloride, on the other hand, is insoluble in diethyl ether but easily soluble in water. This Bulletin describes the determination of cinchocaine in ointments, creams and injection solutions by means of differential pulse polarography. An acetate buffer pH = 4.8 is used as the supporting electrolyte. The limit of quantitation and the linear working range of the method are given. The necessary sample preparation steps are also dealt with in this Bulletin.