Diarrhea in puppies can be a nothing to worry about, or it can be a very serious situation. There are many causes for diarrhea: stress, a change of food, worms, an infection or virus, or parasites. Oftentimes, simple home remedies may do the trick to get your puppy's bowels working correctly; however, do not be surprised if your vet wants to see your puppy right away, especially if he is less than 2 months old.
Communication with your vet is a must. He will ask you a set of questions about the consistency of the stools and other symptoms your puppy may be experiencing such as dizziness or weakness. He will give you an initial course of action, which may include bringing the puppy in for an examination and bringing a stool sample. If you see blood in your puppy's stool, you should immediately call your vet or animal hospital, even if it's in the middle of the night.
One of the most important things to do is to keep your puppy hydrated. Dehydration can lead to serious complications such as difficulty in breathing and seizures. With that said, continue to give your puppy water while he has diarrhea, unless instructed differently by your vet. If your puppy has runny stools, you may want to give him Pediatric Electrolyte (unflavored) available in the baby aisle at most grocery stores. If needed, add some chicken broth to entice your puppy to drink it.
You can try giving your puppy canned pumpkin, which will help firm up the puppy's stool. Be sure you purchase pumpkin and not pumpkin pie filling, as the cans look similar.
Plain yogurt helps the digestive system and may get it working correctly for your puppy. Try giving a serving (one 6 oz. container) each day to see if that helps firm up your puppy's soft stool. You can add some chicken broth or crushed up puppy treats to encourage her to eat it.
If your puppy eats dry packaged puppy food, she may refuse the canned pumpkin or yogurt. In that case, you may be able to give her anti-diarrhea medication intended for humans, such as Imodium AD for soft stools. You can also give your puppy DiaBac, which is specifically made for dogs. Be sure to call your vet first for dosing amounts for your puppy's breed, size and age.
After trying the home remedies, if your puppy still has diarrhea in 24 hours, you need to call your vet back. He will most likely have you bring your puppy in, if he hasn't already, to find out what the official cause of the diarrhea is. If your puppy has worms or parasites, he will prescribe your dog medication such as heartworm medicine.