Xanax is a common prescription anxiety-reducing medication. You can buy Yellow Xanax as a treatment medication if you are diagnosed with an anxiety disorder by your doctor. The Yellow Xanax looks exactly the same as other Xanax bars, and the only difference is its color and imprint code. These bars are yellow in color and imprinted with “R 0 3 9” because the Actavis Pharmaceutical group supplies them.