Best contact your Vet ASAP here as the foaming bothers me and make sure the puppy is drinking. At his age he can catch anything. Good luck and please let me know how he does?
I have a 4 week old puppy that is foaming at the mouth, weak, stomach spasms, crying like he is in pain. I do know that the puppy has been eating his mothers dog food instead of puppy food?
