Xanax is the most prescribed anti-anxiety medication, also known as Alprazolam. It affects brain chemicals that may be imbalanced in anxious individuals. Xanax is used for treating depressed anxiety, panic, and anxiety. Yellow Xanax bar Yellow Xanax bar is basically the same as the original Xanax. The function and the work are the same; the only things that make it stand out are the color, rectangular shape, and the imprint R039. Yellow Xanax bar is the low strength Xanax among all with a strength of 2 mg. It is designed so that it can be easily broken into two-piece and taken in equal quantities both in the morning as well at night. It kicks in after 30 minutes and relaxes the brain nerve by releasing calming effects on ii.