The medication Xanax is used to treat the symptoms of anxiety and panic. It provides soothing effects to the brain and the central nervous system (CNS). Xanax comes in many strengths; Green Xanax Bars are the 2mg form of Xanax which look rectangular-shaped, green, 15.00 mm size, 2mg strength, and have imprinted S 90 3 on them. Green Xanax Bars 2mg belongs to the class of benzodiazepines medication, which acts directly on the brain by increasing GABA (gamma-aminobutyric acid), which blocks the impulses between the brain and the nervous system change the way the brain feels).