Preparations made from Uncaria gambir or Acacia catechu are called hái-ér-chá, băi-yào-jiān, or a-sen-yaku. Their identification and relation to one another are discussed historically and etymologically. Hái-ér must have been derived from khadira (Sanskrit), khayer (Bengalese), or khair (Hindi). A-sen is supposed to be formed by the combination of er and sen; the latter may be a euphonic transformation from sen, to (--, to decoct).