Green Xanax bar is a rectangular bar containing 2mg of Alprazolam, which can be used to treat anxiety, panic disorder, GAD, and co-morbid depression. Green Xanax bars have a fast-acting drug that starts working within 20 minutes. The half-life of this drug is six to eight hours and it belongs to the benzodiazepine class of drugs. It acts by enhancing Gamma-aminobutyric acid (GABA), which is linked to stress reduction. It is mainly effective for people suffering from anxiety and panic disorder as a result of chronic or acute stress.