Frogs do not cause warts. Warts are caused by the human papillomavirus (HPV), which is a strictly human virus. You cannot catch it from a frog, a toad, or any other animal. The myth likely persists because toads in particular have bumpy, rough-looking skin that resembles warts, but those bumps are something else entirely.
Why Toads Look Like They Have Warts
The bumps covering a toad’s skin are not warts. They’re clusters of glands that produce and store toxic secretions used as a defense against predators. The most prominent of these are the parotoid glands, two large oval structures positioned just behind the eyes. When a predator attacks from the front, these glands can release poison in concentrated jets.
Smaller glands are spread across the rest of the body, giving the skin its characteristic rough texture. These glands produce a mix of compounds, including steroids and proteins, that make toads taste terrible and can irritate the mouths and eyes of animals that try to eat them. Frogs tend to have smoother skin than toads, but many frog species also have visible bumps from similar glands. None of these structures have anything to do with HPV or human warts.
What Actually Causes Warts
Warts are small, rough skin growths caused by HPV entering the body through tiny cuts, scrapes, or breaks in the skin. There are over 200 types of HPV, and different types cause warts in different locations. Common warts on the hands are typically caused by HPV types 2 and 4. Plantar warts on the soles of the feet are most often linked to HPV type 1.
The virus spreads from person to person through direct skin contact or through contaminated surfaces. Research has found HPV on public restroom door handles, washbasins, and sink surfaces, meaning you can pick up the virus without touching another person at all. People who already have a wart can also spread it to other parts of their own body, a process called autoinoculation. Biting your nails or picking at a wart, for example, can transfer the virus to your fingers or mouth.
Children and teenagers get warts more often than adults because their immune systems haven’t built up defenses against the common HPV strains yet. People with weakened immune systems are also more susceptible.
Where the Myth Comes From
The idea that touching a toad gives you warts has been around for centuries. The Burke Museum traces it to the simple visual resemblance between toad skin and wart-covered human skin. Before anyone understood viruses, it was a reasonable guess: if toads are covered in bumps and you get bumps after touching one, maybe the toad gave them to you. The timing probably lined up occasionally by coincidence, reinforcing the belief. Warts can take weeks or months to appear after HPV infection, so a person who handled a toad might not develop a wart until long after they’d forgotten the actual exposure.
Real Risks of Handling Frogs and Toads
While frogs and toads can’t give you warts, handling them does carry other risks worth knowing about. The most significant is Salmonella. Frogs and toads commonly carry Salmonella bacteria in their digestive tracts, even when they appear perfectly healthy. You can pick up the bacteria by touching the animal or anything in its environment, including tank water. The CDC considers amphibians more likely than most other pets to carry harmful germs, and recommends that children under five avoid handling them altogether.
Some species also pose a toxin risk. Cane toads, for instance, can squirt secretions that cause severe eye pain, temporary vision problems, and irritation on contact. If swallowed, cane toad toxin can affect heart function, blood pressure, and breathing. Most common backyard toads produce milder secretions, but these can still irritate your eyes or mouth if you touch your face after handling one.
The simple fix for all of these risks is washing your hands thoroughly with soap and water after any contact with a frog, toad, or their habitat. That habit protects you from the things amphibians can actually transmit, even though warts aren’t one of them.
Getting Rid of Warts
Most warts eventually clear on their own as your immune system learns to fight the virus, but this can take months or even years. Over-the-counter treatments containing salicylic acid work by gradually peeling away the infected skin layers. Cryotherapy, where a doctor freezes the wart with liquid nitrogen, is another common option. Clinical trials show both approaches have similar success rates, around 55 to 56 percent for stubborn warts. Some warts resist multiple rounds of treatment, particularly plantar warts that grow deep into the thick skin of the foot. For these, doctors may try other approaches, but patience is often part of the process regardless of the method.
Preventing warts in the first place comes down to limiting your exposure to HPV. Avoid walking barefoot in public showers or pool areas. Don’t share towels or razors. Keep cuts and scrapes covered. And if you already have a wart, resist picking at it to avoid spreading the virus to other parts of your skin.