Of course, even a vaccinated puppy can still encounter health problems now and again. Here are some you may come up against:
Diarrhea

In the majority of cases diarrhea is just a passing inconvenience. Your puppy could suffer from it if he's overly excited or nervous or if he's somehow eaten something unsuitable like the contents of the kitchen trash! However diarrhea can be a symptom of serious illness too and you shouldn't hesitate to take your puppy to the vet if you are at all concerned. Always take him to the vet if the diarrhea lasts longer than twenty-four hours, has blood in it, is accompanied by other signs of illness such as breathing difficulties or if your puppy becomes lethargic or 'floppy' as there is a risk of dehydration in puppies with diarrhea.
Vomiting
Your puppy is bound to vomit occasionally and, most of the time, he'll just need a little TLC. Like diarrhea though, vomiting can be a symptom of serious illness and you should always take your puppy to the vet if the vomiting lasts more than twenty four hours, has blood is it, is projectile or is accompanied by other signs of illness. Again, keep an eye out for the signs of dehydration as this can happen very quickly. Above all, trust your instincts and take your puppy straight to the vet if you are at all worried.