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Updated on September 23rd, 2025
Pet's info: Dog | Mixed Breed Small (up to 22lb) | Male | unneutered
Hi. This substance is always on my dog’s penis, even if he’s just peed and I cleaned him. It doesn’t smell like anything, does pees normally, no signs of pain or struggle, pee usually is normal or is in an spraying action which I think is when he’s marking. He had X-rays a few weeks ago, which I’m attaching both substance and x-ray photo below. Is it worrying? What’s the substance? Is there anything unusual in his x-ray?
5 Answers

Answered By Stephanie Echols, DVM
Veterinarian
Published on March 11th, 2020
Answered By Dr. Leigh, DVM
Veterinarian
Published on March 1st, 2017
Many male dogs will have a small amount of thick, white/yellow discharge from the prepuce, which is called smegma. It is usually a normal occurrence unless there is an excessive amount, excessive licking, or you see any redness or swelling
1Pet Parents found this answer helpful
Answered By Andrea M. Brodie, DVM
Veterinarian
Published on November 3rd, 2016
Yes, there can be a discharge. This must not necessarily be seminal fluid. Many unneutered male dogs have a chronic infection of the prepuce which can show as a clear to milky, sometimes yellow or greenish discharge. If he does not lick his penis constantly and it does not bother him, then this is nothing to worry about. Castration will usually cure it.
1Pet Parents found this answer helpful
Answered By Ricardo Fernandez, DVM
Veterinarian, Veterinary Oncology Resident
Published on September 26th, 2017
Thanks for using Petco Pet Education Center, formerly Petcoach! This discharge you describe could be something called smegma which is normal and expected. However, if this discharge is excessive thick, yellowish and has a foul odor associated with it and the tip of his penis is red/irritated, have him evaluated by your veterinarian as this could be a sign of infection which may require antibiotic therapy. Good luck and have a good day!
1Pet Parents found this answer helpful
Answered By Jenna Beyer, DVM, MBA, cVMA
Veterinarian, Certified Veterinary Acupuncturist
Published on August 4th, 2017
It is quite possible that the discharge you are seeing is smegma. This is a normal occurrence in dogs. It does have more frequently in dogs that have not yet been neutered, but can occur in any male dog. I would just wipe it with a clean towel. If it keeps coming back, if the penis becomes discolored, if Bailey seems painful, or if he has trouble urinating, this could indicate infection and Bailey would need to be seen by a vet as soon as possible.
1Pet Parents found this answer helpful