How many milligrams in a Xanax bar?

A Xanax bar will contain 2 mg of alprazolam (a benzodiazepine axiolytic drug,) which is the active ingredient in xanax. Other dosage forms, however, are available. Alprazolam, at least in the US, is available in 0.25, 0.5, 1, 2, and 3 mg doses, with the 3 mg dose being extended release only.