There are many types of antibiotics—antibacterials, antivirals, antifungals, and antiparasitics. Some drugs are effective against many organisms; these are called broad-spectrum antibiotics. Others are effective against just a few organisms and are called narrowspectrum antibiotics. The most commonly used antibiotics are antibacterials. Your child may have received ampicillin for an ear infection or penicillin for… Read More: Who is the inventor of antibiotics »