To the Editor:— The following note concerning the use in six patients with paroxysmal auricular tachycardia of Rauwolfia serpentina, by which three patients were improved, may be of some interest to your readers. 1. During 1952 and 1953 I treated a white woman, aged 78 years, for cardiac decompensation incident to coronary sclerosis. During July, 1953, the patient was admitted to the Pennsylvania Hospital to control the symptoms of cardiac failure. For some 50 years the patient had suffered from bouts of rapid heart action lasting from 1/2 hour to 12 hours and recurring as often as two to three times weekly. It should be noted that she was highly nervous and excitable, although always most cooperative and helpful. Because of an exacerbation of her nervous state in 1954, and because she reacted poorly to the usual sedatives, I prescribed reserpine (Serpasil), 0.25 mg. to be taken twice daily. From