Yellow Xanax an anxiety medication. The strength of them typically 0.25mg ,0.5 mgs ,1 & 2 & 3 mgs. They can come in yellow ,blue & green and the generics can all be white. But the mg. Is on the pill.whatever the color. They’re only by prescription. I use to be prescribed Yellow Xanax. They turned my life upside down I would do stuff and not remember doing it.