Neosporin Original ointment contains three antibiotics: bacitracin zinc, neomycin sulfate, and polymyxin B sulfate. These are suspended in a petroleum jelly base along with a handful of moisturizing inactive ingredients. The formula is designed for minor cuts, scrapes, and burns, and it’s sold over the counter as a first aid product.
The Three Active Antibiotics
Each gram of Neosporin Original contains bacitracin zinc (400 units), neomycin sulfate (3.5 mg), and polymyxin B sulfate (5,000 units). These three antibiotics target bacteria in different ways, which is why the combination is called “triple antibiotic ointment.” Using multiple antibiotics at once makes it harder for bacteria on a wound’s surface to survive.
Bacitracin interferes with how bacteria build their outer cell walls, weakening them structurally. Neomycin disrupts protein production inside bacterial cells, preventing them from growing and multiplying. Polymyxin B damages bacterial cell membranes directly, causing them to leak and die. Together, these three cover a broad range of common skin bacteria, including both the staph and strep species that most often infect minor wounds.
The Inactive Ingredients
The base of the ointment is petrolatum, commonly known as petroleum jelly. This gives Neosporin its thick, greasy texture and serves a practical purpose beyond just carrying the antibiotics: petrolatum creates a moisture barrier over the wound that keeps it from drying out. Moist wounds generally heal faster and scar less than wounds left exposed to air.
Beyond petrolatum, Neosporin contains cottonseed oil, olive fruit oil, cocoa seed butter, sodium pyruvate, and vitamin E (listed as tocopheryl acetate). The oils and cocoa butter add to the ointment’s moisturizing properties, while vitamin E is included as an antioxidant that may support skin repair.
Neosporin Plus Pain Relief
The “Plus Pain Relief” version of Neosporin adds a fourth active ingredient: pramoxine hydrochloride at 10 mg per gram. Pramoxine is a topical anesthetic that numbs the skin’s surface, reducing the sting and itch of a fresh wound. It works by temporarily blocking nerve signals in the area where you apply it. The three antibiotics remain the same as in the original formula.
How Neosporin Differs From Polysporin
Polysporin contains only two of the three antibiotics: bacitracin and polymyxin B. The key difference is that Polysporin leaves out neomycin. This matters because neomycin is the ingredient most likely to cause an allergic skin reaction. If you’ve used Neosporin and noticed redness, itching, or a rash that seemed worse than the original wound, neomycin is the most likely culprit, and switching to Polysporin eliminates that risk.
Neomycin Allergy Is Surprisingly Common
Allergic contact dermatitis from neomycin is one of the more common topical medication allergies. A large meta-analysis found that roughly 3.2% of adults and 4.3% of children with dermatitis test positive for neomycin allergy. In North America specifically, rates are higher: about 6.4% of adults and 8.1% of children. The reaction typically shows up as redness, swelling, and itching at the application site, which can look a lot like an infected wound getting worse. This leads some people to apply even more Neosporin, making the reaction worse.
If a minor wound seems to be getting more irritated after you apply Neosporin rather than improving, stop using it. Plain petroleum jelly keeps the wound moist and protected without the allergy risk and is a reasonable alternative for clean, minor wounds that don’t show signs of infection.
What Neosporin Is (and Isn’t) Meant For
Neosporin is labeled for first aid use on minor cuts, scrapes, and burns. You apply a thin layer to the cleaned wound one to three times a day. It’s intended for short-term use on small, superficial injuries.
It is not designed for deep wounds, puncture wounds, animal bites, or serious burns. It also won’t help with viral or fungal skin infections, since all three active ingredients target only bacteria. For wounds that are deep, show spreading redness, produce pus, or aren’t improving after a few days of basic care, topical antibiotic ointment isn’t a substitute for professional treatment.