Teething puppies can develop digestive issues with diarrhea and sometimes vomiting. Puppy teething begins around 3 months of age and can last until the puppy is 9 to 12 months old. A young puppy with diarrhea should visit the vet, because puppies can dehydrate quickly.
A puppy has 28 teeth that come in by the time he's 8 weeks old. These teeth, called milk teeth, allow him to begin eating and digesting solid food. By the time he's 3 to 4 months old, his central incisors begin to fall out, followed by the canine teeth and then the premolars. The chewing that defines puppyhood will alert you to intense teething times or you may find tiny teeth around the house. Adult teeth may be right behind the puppy teeth in the gum, adding to your puppy's discomfort and need to chew.
As your puppy loses teeth and the replacements erupt, he will drool more frequently. Swallowing this fluid can upset his digestion and cause diarrhea. A teething puppy will chew on anything he can get into his mouth, and puppies frequently become sick because of something they've ingested, so be sure your house is puppy-proofed during this time period.
Withhold food from your puppy for up to 12 hours while he has diarrhea. Avoid feeding his regular diet until his digestive system returns to normal. He can have boiled chicken breast, shredded, mixed with white rice in small amounts. A puppy should always have access to water. Encourage him to drink to avoid dehydration. Add warm water to the chicken and rice mixture to increase his fluid intake.
See the Vet
If your puppy has diarrhea, call your vet for instructions. Although diarrhea in an adult dog can be less serious, a puppy can dehydrate quickly and complications can arise. Your vet will tell you whether you can wait and observe the puppy or ask to see him to check for other causes, such as worms. If the diarrhea is accompanied by vomiting, blood, lethargy or abdominal pain, don't wait. Take your puppy to the vet as soon as possible.