<human>: My puppy stayed at an emergency hospital since Friday night until last night. While at the hospital he had diarrhea a few times but no vomit. Yesterday he didn't have a bowel movement, although the doctor said he had eaten, until I brought him home (the vet said he no longer required hospitalization and gave me medicine for my pup). A couple of hours after my puppy ate he had a black- brownish tarry stool. I took him back to the vet this morning to explain my observations. He said the mucus-tarry substance came from his intestines, which is normal. 

He's eaten and drinking on his own as well as playing. I'm happy that he's gotten better since Friday, however I'm concerned about the sudden change in his stool.

Can you summarize the given text in a few sentences?
<bot>: Parvo puppy received treatment for 4 days, doctor OK'd his release, stool changed from slightly bloody diarrhea to black slightly runny tarry mucus. Eating and drinking well though.