Dogs seem to lick anything but that doesn't seem to affect their health. I can't seem to reconcile this with normal hygienic theory.

  • Same with cats. It really surprises me. Cats are much more cleaner. But it is because they spend a lot of time licking themselves. If we humans instead of using shower, started using licking as a way of cleaning ourselves, I wonder what would happen. In fact this question is one of the biggest mystries for me.
    – Sonevol
    Jan 26, 2018 at 13:48
  • Not a dog expert, but should apply for dogs as well, cat never lick anything, they lick only for three purposes, 1. Food, 2. Cleaning, 3. Showing affection.
    – Sonevol
    Jan 26, 2018 at 13:58
  • @Sonevol My dog will lick so many things, for reasons that appear so inexplicable, that "anything" is only slightly inexact. It's a reasonable question. But I suspect that it's just as reasonable to ask whether our aversion to licking anything is as related to getting sick as we might assume. Perhaps the range of things we humans can lick without ill effect (if we wished to) are much wider than we assume. Anecdotal data: babies will put anything in their mouth, and other than causing parental panic, they don't seem to be the worse for it (truly dangerous items notwithstanding).
    – LG1
    Jan 31, 2018 at 19:20

1 Answer 1


Dogs have a higher saliva PH and helpful bacterias in their saliva that allow them to ingest bacterias that usually make humans sick, also most illnesses humans contract, animals do not.

Please note, humans can contract human illnesses from dog saliva, feces, urine, or blood.

Pet 'Kisses': Health Hazard or Health Benefit?

The Benefits of Pet Saliva

The belief in the curative power of a dog’s lick dates back to ancient Egypt and has persisted through time. In modern France a medical saying translates to “A Dog’s Tongue is a doctor’s tongue.” Recent research has identified products in saliva that indeed aid in healing.

  • Researchers in the Netherlands identified a chemical in pet saliva called histatins. Histatins speed wound healing by promoting the spread and migration of new skin cells.
  • Dr. Nigel Benjamin of the London School of medicine has shown that when saliva contacts skin it creates nitric oxide. Nitric oxide inhibits bacterial growth and protects wounds from infection.
  • Researchers at the University of Florida isolated a protein in saliva called Nerve Growth Factor that halves the time for wound healing.

Dog Saliva: 5 Fast Facts You Should Know

Dog saliva is antibacterial. “Dog saliva does contain chemicals that are antibacterial and it’s very unlikely that saliva by itself would be a direct cause of infection,” says Harvey. “You often see dogs licking wounds and that is a cleansing action and an antibacterial action to promote the healing of a superficial wound.” Of course licking won’t cure all superficial infections in dogs, so veterinary visits are still often necessary.

Dog “kisses” may transfer bacteria to humans. Just because dog saliva has antibacterial properties does not mean that dog “kisses” are clean and humans should let their guard down. Dr. Edward R. Eisner, the first veterinarian to become a board-certified specialist in Veterinary Dentistry in Colorado, notes that it’s possible for bacteria to be transferred from pets to humans. One study published in Oral Biology in 2012 found that there can be a transmission of periodontopathic species of bacteria between dogs and their owners.

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