This drug is a derivative of aniline combined with acetic acid. It has also been called antifebrin because it acts to bring down a fever. Its chief effect is to relieve pain.

Thus acetanilid is a constituent of many common headache remedies. Nevertheless, because it is derived from aniline, acetanilid is a poison and should never be taken except when prescribed by a doctor. An overdose of acetanilid depresses the action of the heart; it also interferes with the ability of the red blood cells to carry oxygen so that the person affected becomes blue and short of breath.