A nonaqueous titration procedure is described for determining aminoacetic acid and nicotinic acid in mixtures and elixirs. The effect of acetylated aminoacetic acid on the potentiometric titration of nicotinic acid is discussed. Above a 2:1 ration of aminoacetic acid to nicotinic acid, the former interferes with titration. The titration curve of nicotinic acid becomes progressively flatter with increasing amounts of the acetylated compound. Above this ratio, nicotinic acid had to be separated from the mixture by dissolving in ethanol for a successful titration.