Treats infections. Amoxycillin is a penicillin antibiotic used to treat bacterial infections. Amoxycillin also is used sometimes to prevent anthrax infection after exposure and to treat anthrax infection of the skin and chlamydia infections during pregnancy. Talk to your doctor about the possible risks of using this prescription for your condition.Before taking -#tell your doctor and pharmacist if you are allergic to amoxicillin, penicillin, cephalosporins, or any other prescriptions.