Texas house geckos are not poisonous. They produce no venom and carry no toxic substances in their skin, muscles, or organs. The small, pale lizards you find clinging to walls and ceilings near porch lights are Mediterranean house geckos, and they pose no direct danger to humans or pets through touch or a bite. That said, there is one indirect health risk worth knowing about, especially if you have cats.
Identifying the Common Texas House Gecko
The gecko you’re most likely seeing in and around Texas homes is the Mediterranean house gecko. Adults reach 4 to 5 inches long, including the tail. Their skin has a distinctly warty texture, and their color ranges from whitish to pink or tan with brown blotches across the back. Young geckos often show dark crossbands on the tail that fade with age. Their most recognizable features are large, bulging eyes with vertical pupils and wide toe pads that let them walk straight up walls and across ceilings.
These geckos are nocturnal, so you’ll almost always spot them at night, usually near outdoor lights where insects gather. They’re not native to Texas but have been well established across the southern United States for decades.
Why They’re Not Dangerous to Humans
House geckos have no venom glands and no mechanism for delivering toxins. Their tiny teeth can barely break human skin, and even if one does manage to bite (which is rare and usually only happens if you grab one), there’s no medical concern beyond a minor pinch. They don’t sting, and handling one won’t cause a rash or allergic reaction. The common belief that geckos are poisonous likely comes from a general wariness of reptiles, but these animals are completely harmless to people.
The Real Risk: Cats That Eat Geckos
While the gecko itself isn’t toxic, cats that hunt and eat geckos can pick up a liver parasite called a liver fluke. This is the origin of the old term “lizard poisoning” in cats. The name is misleading because the cat isn’t being poisoned by the lizard’s body. Instead, geckos (along with skinks, anoles, and toads) can carry an intermediate stage of a parasitic fluke in their bile ducts. When a cat eats an infected gecko, the parasite migrates to the cat’s liver and bile ducts, where it matures and causes damage over time.
This parasite is well documented across Florida, other southeastern states, Hawaii, and parts of Texas. Prevalence in tropical and subtropical environments ranges from 15% to 85% of outdoor cats, with the highest rates in cats that are allowed to hunt freely. Mild infections cause temporary loss of appetite, low fever, lethargy, weight loss, and a dull coat. Severe or chronic infections lead to vomiting, jaundice, diarrhea, and eventually liver failure.
If your cat regularly catches geckos or other small lizards, this is worth discussing with a veterinarian. Indoor cats obviously face no risk, and dogs are not typically affected by this particular parasite.
Salmonella: A Minor Concern
Like most reptiles, house geckos can carry Salmonella bacteria on their skin and in their droppings. For humans, the risk is low as long as you wash your hands after handling a gecko or cleaning up droppings. The concern is slightly higher for young children, elderly adults, and anyone with a weakened immune system. You don’t need to sanitize your entire house if a gecko gets inside, but wiping down surfaces where gecko droppings accumulate (windowsills, counters near exterior doors) is a reasonable precaution.
What House Geckos Actually Do in Your Home
Far from being a pest, house geckos function as free insect control. Their diet consists almost entirely of insects and small arthropods. They eat mosquitoes, earwigs, leafhoppers, ants, caterpillars, spiders, and pillbugs. Geckos living on or inside buildings eat particularly large quantities of grasshoppers. Juveniles tend to go after smaller prey like leafhoppers and flies, while adults tackle bigger insects.
A gecko hanging near your porch light at night is actively reducing the number of mosquitoes, moths, and other insects around your home. They’re quiet, they don’t chew wires or insulation, and they don’t reproduce in large enough numbers indoors to become a nuisance. Most pest control professionals in Texas consider them beneficial and recommend leaving them alone.
If you’d rather not share your living space with them, sealing gaps around doors, windows, and utility lines is the most effective approach. Reducing outdoor lighting or switching to yellow bulbs that attract fewer insects will also make your home less appealing to geckos looking for an easy meal.