It might be hard not to sometimes, but is it safe and healthy to kiss your dog? Generally, yes. Bacteria that may be in your dog’s mouth (i.e., from what he eats and licks) is usually safe for humans. As long as you’re not grossed out, go for it, but have some awareness of what your dog has been doing lately.
You might be wondering if you and your dog can get each other sick. Parasites like giardia, hookworm, and roundworm can be passed between species. Salmonella can also be passed between you and your dog. However, most viruses and bacteria only affect one species or the other – so, no, you won’t give your dog your cold.
If you’re immune-compromised (such as if you’re sick with HIV/AIDS, or if you are a cancer patient or a recipient of an organ transplant) it’s smart to avoid kissing pets altogether. This minimizes the risk of infection when your body can’t fight one off.
Finally, keep in mind that not all dogs are comfortable with your face super close to theirs. Read your dog’s body language and signals to make sure that this sign of affection is welcome.