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Why does my male dog's penis swell on one side? Is it a concern?

Updated On September 23rd, 2025

Pet's info: Dog | Mastiff | Male | unneutered | 2 years old | 95 lbs

some times my male dogs penis swells up on one side or another what is happening is it a concern?

1 Answer

Most Helpful Answer

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Answered By Ann Dion, DVM

Veterinarian

Published on April 6th, 2017

Hello. If there is a swelling on either side of the penis, that looks like two marbles (can be big marbles) that are under the skin, and they come and go, this is likely his 'bulbo-urethral glands' and this is normal. If this is not the case, and there are other or different looking masses then you should have him seen. Neutering will help decrease the frequency of this occurring, and his risks of testicular cancer, and will help with behaviour as well. Good luck with Buddy.

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