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My dog has diarrhea and green discharge after vaccine. Should I worry?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Medium (23 - 60lb) | Male | neutered | 1 year and 9 months old

My dog just had his first yearly vaccination on Monday, starting yesterday (Wednesday) I noticed he had diarrhea, and still has it as of Thursday evening. Should I be concerned or will is this fairly normal and will pass? I also noticed he had slightly green tinged discharge from his penis, not a lot but enough to worry me.

1 Answer

Most Helpful Answer

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Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on May 9th, 2019

Thank you for contacting Petco Pet Education Center, formerly Petcoach with your question. You can see some diarrhea after vaccines, but it should pass within 48 hours. If Milo is still having diarrhea tomorrow morning, have him seen by a vet. The green discharge may be normal. It's called smegma, and it actually comes from the penile sheath. I hope this helps!

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