A simple method for determination of L-ascorbic acid of(1-50) ug/ml in pure form and pharmaceuticals is described. The rapid procedure is based on the direct visual titration of L-ascorbic acid with ceric ammonium sulphate in the presence of chlorpromazine hydrochloride in a mixture of sulphuric and phosphoric acids as a redox indicator. © 1990, Taylor & Francis Group, LLC. All rights reserved.