Sulfa drugs are medications used to treat a variety of infections and medical conditions. Sulfa drugs were among the first antibiotics ever developed and are still some of the most effective. They work by killing bacteria.

Sulfa drugs are available in many different forms, including tablets, capsules, and liquid. They may also be available as a cream, ointment, or powder. Most sulfa drugs are taken by mouth, but sulfa drugs also exist as intravenous (IV) drugs.

Sulfa drugs are available in various strengths. The strongest sulfa drugs are called penicillin.