It could be from worms or the dogs anal glands. This can be done at the vet or at the groomers. If it's not done correctly it could cause serious health problems for the dog. If it worms the vet can let you know. Worms usually don't leave the body on their own with out meds or if they have a lot.

If your dog has diarrhea and is vomiting I would call the vet right away. It could be from something they ate and is making them sick but it could be worse like an allergy or parasite. Act quickly to be on the safe side and ask a vet.

I think this is something that some dogs do (or try to do). I doubt they do it because they are hungry or lacking something in their diet. Some dogs will eat just about anything if they are able to. Just like some dogs try to get into the trash can and eat whatever is in there which is why trash cans with lids are really great. I used to watch a dog that tried to eat socks all the time! Teaching the dog not to eat poop would be the best idea, especially because they could get serious sick from poop and also because it's just gross. 💩 I would suggest that when you take your dog for a walk to make sure you are watching and making sure that your dog doesn't come across any poop. It might sound ridiculous but it's going to mean that you are in a sense going to have to make sure you keep your dog away from all the poop outside. Then if your dog does come across some poop and decides to "try it" you can stop your dog before hand. Tell your dog no. Direct the dog away from the poop. At first your dog will most likely try reaching towards it anyway. I would either pick my dog up and remove my dog from the poop or if my dog was too big for that then I would help guide the dog away maybe like giving it a hug and walk at the same time or whatever. Every time you take your dog out for a walk and you say no and your dog listens or gets better about it then give your dog a treat. A treat has got to taste way better than poop right?