Why are dogs’ mouths cleaner that humans?

Why are dogs’ mouths cleaner than humans?


It’s a common belief that a dog’s mouth is cleaner than a human’s mouth. However, the reasoning behind this belief is not well understood. While it’s true that dogs don’t brush their teeth or use mouthwash like humans do, their mouths are still considered to be cleaner in some respects. In this article, we’ll explore the reasons why dogs’ mouths are thought to be cleaner than humans’ and examine the science behind it.

Dog saliva and its composition

One explanation for why dogs’ mouths are cleaner than humans’ is the composition of their saliva. Dog saliva contains lysozyme, an enzyme that can destroy harmful bacteria. Lysozyme is also found in human saliva, but at a lower concentration. Additionally, dog saliva has a lower pH than human saliva, which can help prevent the growth of bacteria. The high concentration of antibacterial properties in their saliva can help eliminate harmful pathogens in their mouths.

Enzymes in dog saliva

Dogs have a variety of enzymes in their saliva that can help break down food and reduce the amount of bacteria in their mouths. One of these enzymes is amylase, which helps to break down carbohydrates found in food. Another enzyme, lipase, helps to break down fats. The presence of these enzymes can help reduce the amount of bacteria in a dog’s mouth, keeping their teeth and gums healthier.

Bacteria and the oral microbiome

The oral microbiome refers to the collection of microorganisms that live in the mouth. In dogs, there is a diverse and complex community of bacteria that can help promote oral health. For example, the bacteria in a dog’s mouth can help break down carbohydrates and protect against harmful pathogens. The balance of bacteria in a dog’s mouth can play a crucial role in maintaining oral health.

Human oral hygiene and bacteria

Humans, on the other hand, are more likely to have a disrupted oral microbiome due to poor oral hygiene practices. Brushing and flossing teeth are essential to maintaining a healthy oral microbiome. However, the use of antibiotics, medications, and other factors can also disrupt the balance of bacteria in the mouth, leading to an increased risk of oral health problems.

Self-cleaning mechanism in dogs

Dogs have a natural self-cleaning mechanism in their mouths, which can help to reduce the amount of bacteria. When a dog chews on bones or toys, it can help remove plaque and tartar buildup on their teeth. Additionally, the act of licking itself can help remove debris and bacteria from the mouth.

Bacteria and immune system in dogs

Dogs have a robust immune system that can help fight off harmful bacteria in their mouths. Their immune system can help protect against oral infections, such as gum disease and tooth decay. Additionally, the immune system can help prevent bacteria from spreading to other areas of the body.

Human immune system and oral hygiene

Human immune systems also play a crucial role in oral health. However, the immune system can only do so much to protect against harmful bacteria in the mouth. It’s essential to maintain good oral hygiene practices to reduce the amount of bacteria in the mouth and keep the immune system working optimally.

Risk of disease transmission from dogs

While dogs’ mouths may be cleaner than humans’, there is still a risk of disease transmission. Dogs can carry harmful bacteria, such as Salmonella and E. coli, that can be transmitted to humans through licking or biting. It’s essential to wash hands thoroughly after handling dogs and to avoid letting them lick open wounds or cuts.


In conclusion, dogs’ mouths are thought to be cleaner than humans’ due to the presence of antibacterial properties in their saliva, a diverse oral microbiome, and a natural self-cleaning mechanism. However, it’s essential to maintain good oral hygiene practices in both dogs and humans to reduce the risk of oral health problems and disease transmission.

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