Common side effects of Xanax include drowsiness, confusion, and slurred speech. Less common side effects include memory loss, depression, and difficulty concentrating. In most cases, these side effects are mild and go away after a few days of taking the medication. However, some people may experience more serious side effects, such as hallucinations or aggressive behavior. If you experience any of these side effects, it's important to contact your doctor immediately. Memory loss is a rare but potential side effect of taking Xanax. If you're concerned about this possibility, talk to your doctor about alternative treatment options.