What is Xanax? Xanax is an authorized medication used to treat anxiety disorders and anxiety caused by depression. The medication is from the family of drugs known as benzodiazepines. It is believed that this medicine works by improving the performance of certain neurotransmitters in the brain. People also buy Xanax online for panic disorder without fear of places and situations that may cause helplessness, embarrassment, or panic (agoraphobia).