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Why is my young dog throwing up, skinny, and having black tarry stool?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Small (up to 22lb) | Female | unspayed | 4 months and 29 days old | 10 lbs

My dog tends to just throw up or gag at certain times, she does get car sick and when she gets out she foams at mouth , and her #2 was black liquid like tar looking ... she had worm shots & a penicillin shot . Any ideas of why she throws up? Or won’t gain weight? Her weights not a problem to me right now but everyone else says she’s skinny.

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1 Answer

Most Helpful Answer

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Answered By Dr. Dayna, DVM, CVA

Veterinarian, Certified Veterinary Acupuncturist

Published on November 13th, 2017

There can be a long list of reasons that young dogs throw up. However, I think starting with a broad spectrum deworming is appropriate. If that doesn’t resolve then I would recommend a visit to your veterinarian. If they are throwing up food, but otherwise gaining weight and not sick then I may consider a diet change. However, if the pup isn’t gaining well or I am other wise concerned then I would probably recommend blood work and x-rays to start the diagnostic process. If an answer is not found by the time she is due for spay then I would biopsy the stomach and intestinal tract when I am already in the abdomen for her spay. Best of luck and I hope she improves soon.

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