evidence: No, geckos aren’t poisonous. There are some species of lizard that do have venom, but all of them belong to the Toxicofera family. In contrast, geckos don’t produce any harmful substances. [...] Geckos are absolutely harmless to humans. Not only this, but they’re also very beneficial. These urban geckos are voracious predators of invertebrates of all kinds. [...] As has already been established, geckos aren’t poisonous. They don’t cause any harm and they feed on invertebrates. In addition, they’re very discreet and silent. Their presence in the home can be favorable, so if you do find a gecko, one option is to simply let it be.