My Dog Has Pus Coming From His Penis

My Dog Has Pus Coming From His Penis

A dog's penis health is not always apparent. We may not pay much attention to that area of their body unless we are giving them a bath or if they lie down to expose their belly. This is why it is so important to observe any behavioral changes in our pet. If they are excessively licking their genital area or mounting objects, we should take a look to ensure there aren't symptoms of an underlying pathology.

One of the most visceral signs something may be wrong is when we see a discharge coming from their penis. This is sometimes of a yellow, green or white color. The colors can mean different things, but it if your dog has pus coming from their penis, it is important to know if you have something to worry about. AnimalWised helps highlight those emissions which highlight a health problem as well as those which are normal.

Reasons for penile discharge in dogs

It is true that a dog may lick their penis excessively due to pus, but it is not always the case that there is a problem. There are normal residues and secretions which won't pose any serious health risk to your dog. These are the most common reasons to see discharge and it is important to remember a dog licking their penis is part of their normal hygiene maintenance behavior.

When the discharge is yellowish or green, it is potentially fine, but we need to get a diagnosis to be sure. On rare occasions, it is possibly a sign of infection. If there is any blood in the discharge, it is a cause for concern. Let's look at a list of the possible reasons for penile discharge in dogs before we discuss them in more detail:

  • Urination
  • Ejaculation
  • Smegma
  • Lack of hygiene or dirt accumulation
  • Parasitosis
  • Prepuce infection
  • Sexually transmitted disease
  • Traumatic injury
  • Cancer

What discharge is normal for a dog's penis?

As with a human penis, the dog's member is used for the two main functions of urination and insemination of females. This means there are two main healthy types of discharge which may emanate from the dog's penis, urine and semen.

Dog penises are not the same as all mammals. At the base of the shaft, the dog's penis has the bulbus glandis. This is a rounded part which becomes engorged when they copulate with females and gets stuck to ensure insemination. When a dog's penis is stuck out, it does not mean there is a problem. It will usually just mean they have an erection, something which can occur even if the dog has been neutered.

The outside part of the dog's penis is known as the prepuce and is essentially a canine foreskin. This is a sheath of skin and fur which protects the shaft and glans penis inside. When the dog is not erect, the prepuce should cover the penis. When the dog has an erection, the red or pink mucus membrane will be exposed. This is colloquially sometimes referred to as lipstick for obvious reasons. If the dog's prepuce has some yellow stains around the fur, but is otherwise clean, it will likely be from urine which is of this color.

Dogs practice mounting behavior from before they reach sexual maturity. Like much of the behavior of puppies, their actions are designed to help them when engaging in adult activities. Mounting helps them practice for when they see females in heat as sexually mature dogs. They may masturbate by rubbing their genitals on blankets, couch pillows or anything which will help stimulate their erect penis to ejaculation. If there is a white discharge on their penis, it is possible this is normal ejaculate.

Neutering a dog will seriously reduce their sexual urges and may even prevent them from masturbating. However, it is not likely male dogs will stop mounting all together as they use this action for other reasons such as showing dominance.

Can a neutered dog still produce semen?

Since male dogs which have been castrated no longer have testicles, they will be unable to produce sperm. Other types of sterilization such as vasectomy may still result in sperm production[1]. If this is the case, then they may still have a white discharge in the form of semen. However, ejaculate is not only made from sperm. The majority of a dog's semen is made from liquids which derive from other reproductive organs, although the exact composition is not well known[2]. It is possible the dog will have a white viscous discharge even if they have been neutered.

If there is sperm present in a dog's semen, it should look whiter and thicker. If this is the case, then we need to double check to ensure their sterilization has been effective.

We will discuss some different types of discharge from a canine penis, but there is one which should always be of concern. If your dog has a blood red discharge coming from their penis or if they have blood in their urine, it is likely due to a serious condition. This could be an underlying pathology, an infection or as the result of some sort of trauma. Whatever the cause, you will need to take the dog to a vet for diagnosis.

Yellow discharge from a dog's penis

Many dog groomers will have to shave around the prepuce to get an even look. If they are careful they will be able to do this with no problem. Doing this is often a good time to check for abnormal discharge. The aforementioned urine stains are normal and to be expected. However, the color and consistency is important to look at. Viscous discharge will not be from urine which should be water like in consistency.

Yellowish secretions from a dog's penis may be due to smegma. In mammals, smegma is a secretion which appears on the outside reproductive organs. It is made from skin cells, moisture and oils acting as a lubrication. It can be any range of yellow, but is not often very deep in color. Smegma is often accompanied by a malodorous smell, but it should not be very strong.

In rare occasions, a dog may simply create a large amount of smegma. When this occurs, the dog may decide to lick it from their genitals themselves. There should be no concern if this yellowish substance is present as its presence is not a symptom of a problem. Licking of the genitals is not a good indicator of a health issue as dogs will do it as part of their self-grooming routine. However, excessive licking may be a concern.

Green discharge from a dog's penis

While smegma is a normal secretion of a dog's penis, it will rarely be of a green color. However, it may look a little greenish depending on how much dirt is on the organ. What is more important is to differentiate between normal and abnormal discharge.

Smegma is not normally abundant and is of a thick, almost buttery consistency. Fresh smegma will generally be of a thinner consistency than older secretions. If the color of the discharge is of a strong color, has a bad odor and is in relative abundance, it is more likely to be pus. The presence of pus makes it more likely the sign of an infection. Discerning the difference between pus and smegma is important as it will help us to know if we need to take them to the vet.


The discharge of pus is a sign of infection, one such infection being balanoposthitis. This is when the infection affects the glans (end) and foreskin of the dog's penis. Such an infection can be caused by different agents, but the main two are by a foreign body or by canine herpesvirus.

Foreign bodies can get caught between the prepuce and the penis when they are out in the world. Vegetation, stones or dirt might get in while they are running. The foreign body agitates the mucus membrane, causing friction and irritation. The result may be pus-like substance coming from the penis. The herpesvirus works from within, sometimes being contracted by sexual intercourse and resulting in the presence of pus.

Phimosis is the contraction of the prepuce. The opening is so small that it can interfere with the flow of urine, resulting in infection. It is a condition which may be present at birth or develops later in life.

Does pus mean my dog has an STD?

Sexually transmitted diseases (STDs), also known as sexually transmitted infections (STIs), are relatively uncommon in dogs. However, if your dog has been sexually active, it is still a possibility. There are not as many known varieties as there are in humans. The three main types are:

  • Herpesvirus
  • Transmissible venereal tumor (TVT)
  • Brucellosis

We have mentioned herpesvirus above and we will discuss TVTs in the next section. Brucellosis is an STD which is caused by the passing of bacteria (Brucella canis) via the genitals during copulation. Clinical signs of brucellosis in dogs are not thought to be pathognomonic, i.e. they can share symptoms with many other problems[3]. Purulent discharge is not very common in male dogs, but it is possible. Inflammation is a more common clinical sign.

Does pus on my dog's penis mean they have cancer?

In the majority of cases, abnormal discharge on a dog's penis is easily treatable. The presence of smegma will not likely increase the risk of cancer[4]. If the dog does not lick itself regularly, the lack of hygiene may possibly be a contributing factor, but even this is hard to prove.

However, some penile cancers may lead to discharge. One type is known as canine transmissible venereal tumors (CTVT) which is one of a rare from of sexually transmitted cancers in dogs. There are only three types of cancer in the world which are believed to be transmissible. However, prostate cancer may also lead to abnormal discharge as was the case in a four year old Newfoundland cross dog reported in 2002[5].

The metastasized cancer had reached the penis, resulting in the discharge. It was also accompanied by priapism, meaning continued painful erections. If your dog is neutered and is not near female dogs in heat, their erections should be of a normal consistency. Continued erections or when the dog penis is swollen, may be signs of something problematic. If cancer or a serious infection is present, they will likely be accompanied by other symptoms. This is why it is so important to take your dog to the vet if you see symptoms of a pathology.

My dog's penis has bumps on it

As we stated earlier, if a dog's penis is swollen and stuck out, it could simply be due to a normal erection. Also as we have discussed, a dog's penis has a bulbus glandis. This will appear that there are two large bumps at the base of the shaft, but this is normal. They will go away when the erection does.

However, it is possible there will be bumps, rashes or swelling which are not normal and will need to be addressed. Although rare, it is possible for the dog to develop tumors on their penis, something which may not be observable unless they have an erection. While the lumps may cause discomfort, they probably will not cause itching, so they may not lick their penis excessively.

Other bacterial, viral or fungal infections may cause bumps to appear. So too might parasitical infestations. Injuries might also occur, leading to inflammation or discoloration of the skin. If you see any of these symptoms, you will need to take the dog to a veterinarian to confirm a diagnosis. Treatment will depend on the underlying cause, for example surgery may be needed for tumors or antibiotics for an infection.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to My Dog Has Pus Coming From His Penis, we recommend you visit our Reproductive system diseases category.


1. McDougall, M. K., et al. (1975). The Effects of Vasectomy on the Spermatogenisis in the Dog, Canis familiaris: A Meiotic Analysis. Fertility and Sterility, 26(8), 786-790.

2. Lucio, C. F., et al. (2017). Lipid Composition of the Canine Sperm Plasma Membrane as Markers of Sperm Motility. Reproduction of Domestic Animals, 52(2), 208-213.

3. Hensel, M. E., Negron, M., & Arenas-Gamboa, A. M. (2018). Brucellosis in Dogs and Public Health Risk. Emerging Infectious Diseases, 24(8), 1401-1406.

4. Van Howe, R. S., Hodges, F. M. (2006). The Carcinogenicity of Smegma: Debunking a Myth. J Eur Acad Dermatol Venereol, 20(9), 1046-1054.

5. Rogers, L., López, A., & Gillis, A. (2002). Priapism Secondary to Penile Metastasis in a Dog. The Canine Veterinary Journal, 43(7), 547-549.