The powerful antibiotic penicillin was discovered by Alexander Fleming in 1928 when he observed, by chance, that bacterial growth was inhibited by a contaminating mold (Penicillium). Since then, many synthetic derivatives of penicillin have been made and used for a wide spectrum of applications. Ampicillin is one of the most useful of these derivatives and serves as a highly effective medication to quench many bacterial infections. Side effects include fever, joint pain, swelling, skin rash, hives, and itching.