AN important statement on the anti-malarial drug mepacrine B.P. (quinacrine hydrochloride of the United States Pharmacopoeia, also called 'atebrin' or 'atabrin') has been issued by the Medical Research Council's Committee on Malaria (Brit. Med. J., 664, Nov. 18, 1944, and the Lancet, 667, Nov. 18, 1944). In view of the great importance of malaria in warfare in the Far East and the Mediterranean area, a great deal of work has been done recently on the relative merits of the two chief anti-malarial drugs at present available, namely, mepacrine and quinine. Before the War the world's supply of quinine came almost entirely from Java, and, when the Japanese captured this island, they also cut off practically the whole supply of this essential drug. The Allied Nations turned, therefore, to mepacrine, originally made by the I.G. Farbenindustrie, which announced its manufacture in 1932. Mepacrine has an acridine nucleus with a long side-chain ending in a substituted amino-group. It may stain the skin yellow when it has been taken by the mouth in large quantities. Its manufacturers stated that its anti-malarial action is as powerful as that of quinine, and this was confirmed during the Ceylon epidemic in 1935. One of the advantages claimed for it was that it is less likely than quinine to cause vomiting or to be followed by blackwater fever; but its action was said to be slower and, in a small proportion of cases, it was apt to cause symptoms resembling those of. epilepsy or mania.