Sodium sulfacetamide is a sulfur-based drug that doctors used to prescribe to fight infections long before the discovery of modern-day antibiotics like penicillin and tetracycline. Today, their popularity as an alternative infection-fighter is returning because many strains of bacteria have become resistant to antibiotics. Sodium sulfacetamide is used in acne-fighting products to kill the bacteria that cause acne; it’s also sometimes prescribed to fight rosacea, dandruff and seborrheic dermatitis. Many people are allergic to sulfa drugs. Side effects include irritation, stinging and burning. It is also considered harmful to unborn children.