Hydrogen Peroxide Won't Prevent Tetanus. Here's What Does.

A pharmacist on TikTok posted about a young patient with a deep, contaminated wound and argued that hydrogen peroxide should have been used on it, because the bacteria that cause tetanus are anaerobic (they don't do well in oxygen). The PA who treated the patient didn't use it.

There's a reason for that. Hydrogen peroxide is the wrong treatment for this wound, and the advice in that video is wrong in a way that could hurt someone. I'm a general surgeon and a plastic surgeon (here's why I trained in both), and treating wounds is a big part of what I do. So here's what actually protects a patient like this, and why peroxide isn't part of it.

Tetanus is a severe, often fatal disease. It gets in through damaged, oxygen-deprived tissue, which describes exactly the kind of wound in that video. That's why a deep, dirty wound gets treated with tetanus in mind, not just "keep it clean."

Having had tetanus shots in the past doesn't guarantee you're protected today. Antibody studies have found that a real share of adults, up to about 30% in some studies and more among older adults, have levels too low to prevent tetanus. We also know from studies that a booster raises those levels quickly, which can prevent the disease.

Certain wounds are higher risk than others, and a deep, contaminated wound like this one is one of them. The CDC's wound guidance recommends a booster for a dirty or major wound if your last dose was 5 or more years ago (10 or more for a clean, minor wound), and vaccination for anyone whose history is unknown or incomplete.

Occasionally we also give tetanus immune globulin, ready-made antibodies that protect right away. For a higher-risk wound, it's for patients with an unknown vaccination status and for immunosuppressed patients, on top of the booster.

Giving antibiotics afterward has not been shown to prevent tetanus in a contaminated wound like this, and the CDC doesn't recommend them for that purpose. If the wound gets infected, that gets treated. But antibiotics aren't how we prevent tetanus.

The idea that hydrogen peroxide is a magical cure for wounds has been studied, and it doesn't hold up. Three reasons:

1. It doesn't kill the spores in any realistic amount of time. The spores are what cause tetanus, and they're built to survive harsh conditions. Killing them with hydrogen peroxide takes a couple of hours of continuous contact, not the few seconds it sits in a wound.
2. It breaks down almost immediately. Your blood and tissue, and many common wound bacteria, contain an enzyme called catalase that breaks hydrogen peroxide down into water and oxygen. That fizzing is the peroxide being used up.
3. It damages healthy tissue. Hydrogen peroxide is cytotoxic. It injures and kills cells, including the ones your body needs to heal the wound.

The whole case for peroxide leans on tetanus bacteria being anaerobic. But think about what happens next. A wound like this one gets closed. It may be open to air at first, but once it's closed, it isn't anymore.

And there's no way to eliminate every bacterium from a wound, even with thorough irrigation in the operating room or the emergency room. That's exactly why we don't rely on cleaning alone. Good wound care means cleaning the wound well and removing dirt and dead tissue, closing it when that's appropriate, and protecting you with a booster, plus immune globulin when it's indicated.

The same logic applies to surgical incisions. If yours opens or looks off, call your surgeon instead of reaching for the peroxide. Open incisions are usually managed with a wound-care plan of ointment and dressings, which I cover in why re-stitching a wound after a breast reduction usually doesn't work. And not every bump at an incision is an infection; stitch abscesses are a common example.

None of this is new. When I graduated from medical school in 2003, we already knew hydrogen peroxide wasn't the right option for wounds. It's easy to find on PubMed, and it's the kind of thing a pharmacist should know.

What bothers me most is the confidence. People trust a healthcare credential, so when someone with one tells them to treat a dangerous wound with peroxide, they listen. That's why who should be allowed to post medical advice online is a question worth asking.

• Tetanus is the real risk with a deep, dirty wound, and it gets in through damaged, oxygen-poor tissue.
• A booster is what protects you, because past vaccination doesn't guarantee protective antibody levels today. Some patients also need tetanus immune globulin.
• Antibiotics don't prevent tetanus.
• Hydrogen peroxide doesn't either. It can't kill the spores in the time it's in contact, your own tissue breaks it down within seconds, and it damages the cells trying to heal the wound.

If you have a deep, dirty, or puncture wound, get it seen, and know when your last tetanus shot was.