While the alkaloids from the trunk bark of Alstonia constricta F. Muell. have been quite exhaustively studied in the past, little investigation has been conducted on the alkaloids contained in the root bark. The presence of reserpine in A. constricta root bark was recently reported by Crow and Greet (1), and laboratory results were published by Curtis, Handley, and Sinners (2). A. constricta is a small, often bushy tree, 10-30 feet tall, and its distribution is confined to northeastern Australia. All parts of the plant are extremely bitter, and the inner bark of the stem and roots is a golden yellow. The root bark is relatively thick, being approximately one inch thick on roots four inches in diameter. It is very succulent and loses 80% or more of water when dried. A sample of root bark from New South Wales yielded reserpine (0.05%), tetrahydroalstonine, isolated as the maleate salt, and a third weak base (0.11%), which is apparently the alstonidine of Hesse (3). α-Yohimbine (rauwolscine) was isolated as the hydrochloride from the moderately strong base fraction by a chromatographic procedure. Inasmuch as the purpose of this investigation was to ascertain the feasibility of commercial utilization of A. constricta root bark as a source of reserpine, little was done with the strong base fraction other than to establish the presence of alstonine by paper chromatography. Should the sample examined be characteristic of the root bark generally available, it cannot at this time be considered as an economical source of reserpine.