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Discharge of Foul-Smelling Pus in cats

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

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Discharge of foul-smelling pus in cats is the leakage of thick, often yellowish or greenish secretion from a wound or body opening, which spreads an unpleasant odor. This discharge is usually a sign of an infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. caused by bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease..

Can Occur with the Following Diseases:

Abscess (Pus Collection)

Basics and possible causes

Pus is a product of the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. that occurs when white blood cells flow into the affected area to fight against invading bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease.. These white blood cells, along with dead tissue and bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease., form the pus. The unpleasant odor is caused by the decomposed proteins and bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease..

A common cause of pus formation in cats is bite wounds. Cats have sharp teeth that can cause small but deep wounds. These wounds close quickly over the surface, creating an anaerobicAnaerobic describes life forms or processes that occur in the absence of oxygen. In veterinary medicine, this often refers to anaerobic bacteria that thrive in low-oxygen environments and can cause infections. environment that promotes the growth of certain bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease..

Other causes can be abscesses that form when an infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. is trapped in a limited area of the body. Abscesses often occur in areas that have been damaged by injuries, injections, or foreign objects, such as thorns or splinters.

Gum diseases or infections of the oralOral means "through the mouth" and refers to the intake of food, medication, or other substances through the mouth. In veterinary medicine, many treatments are administered orally. cavity can also lead to pus formation. These are often caused by tartar (calculus) and bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. that attack and inflame the gums.

In rare cases, systemic infections, such as bacterial infections of the blood (sepsisSepsis is a life-threatening condition caused by the body's overwhelming response to an infection, which can lead to damage to its own tissues and organ failure.), or fungal infections can lead to pus formation in various parts of the body.

Typical accompanying symptoms

Wounds or swelling: Cats with pus discharge often have visible wounds or swelling at the affected site, which may be warm or painful.
Fever: An elevated body temperature may indicate a systemic reaction of the body to the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..
Loss of appetite: Cats with infections tend to eat less, which may indicate discomfort or pain.
Lethargy: Infected cats often show a decreased level of activity and withdraw.
Changes in behavior: Aggressiveness or extreme withdrawal may indicate pain or discomfort.
Increased licking: Cats tend to lick the affected area excessively, which may be an indicationIndication refers to a valid reason or rationale for using a specific treatment, medication, or medical procedure. It is based on the diagnosis and the patient's clinical condition. of pain or itching.

When to visit the vet?

A veterinarian should be consulted as soon as signs of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. or pus formation are noticed. A visit is especially important if the cat additionally shows fever, severe pain, or loss of appetite, as this may indicate a more serious infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..

Even if the cat’s condition deteriorates rapidly or new symptoms occur, veterinary advice should be sought immediately. Rapid treatment can prevent the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. from spreading or worsening.

In the case of abscesses or deep bite wounds, a veterinary examination is necessary to ensure the correct treatment, which often includes opening and draining the abscess as well as administering antibiotics.

Symptom recognition for animal owners and veterinary diagnostic procedures

Pet owners can determine the presence of pus by carefully observing the cat. Signs such as swelling, wounds, or the characteristic odor are obvious indicators. The pet owner should try not to manipulate the affected area to avoid worsening the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..

The veterinarian will examine the cat thoroughly, paying particular attention to the affected area. Often, a sample of the pus is taken to identify the specific bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. that are causing the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. This helps in selecting the right antibiotic.

Additional diagnostic procedures, such as blood tests or imaging procedures (e.g., X-rayX-ray is an imaging technique that uses X-rays to create images of the inside of the body. It is often used to diagnose bone fractures, lung diseases, and other conditions. or ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow.), may be necessary to determine the extent of the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. or to rule out other underlying problems.

What can pet owners do and professional therapy options

The pet owner should take care to keep the affected area clean without unnecessarily stressing the cat or worsening the wound. Gentle cleaning with an antiseptic agent can help reduce the bacterial load.

It is important to give the cat enough rest and keep it in a stress-free environment to promote healing. Excessive licking of the wound should be prevented by applying an Elizabethan collar to support healing.

The administration of medications prescribed by the veterinarian, such as antibiotics, should be carried out strictly according to the instructions to successfully combat the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. A complete treatment is crucial, even if the symptoms appear to improve, to prevent a relapse.

Outlook on current research

The discharge of foul-smelling pus in cats is a symptom that can occur with various infections and injuries. Current research focuses on better understanding the underlying microbial causes in order to develop more targeted treatment approaches. One study has shown that certain bacterial strains, such as Staphylococcus spp. and Streptococcus spp., are often associated with pus-filled abscesses. These bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. are often resistantResistant means being insensitive to a substance, drug, or treatment. In dogs and cats, resistance can refer to the ineffectiveness of antibiotics against certain bacterial strains or the insensitivity of parasites to certain pesticides. to common antibiotics, which complicates treatment and underscores the need for the development of new antimicrobialAn antimicrobial substance is an agent that serves to inhibit the growth of microorganisms such as bacteria, viruses, fungi, and protozoa, or to kill them. Antimicrobials are frequently used to treat infections. strategies.

Recent research also examines the role of the cat’s immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. in defending against such infections. Cats have a complex immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. that can respond to infections in various ways. Some studies suggest that certain genetic factors may make cats more susceptible to infections that lead to the formation of foul-smelling pus. These genetic factors could serve as markers for the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of such infections in the future.

Another area of research is the development of vaccines that can protect cats from common infections that lead to pus formation. InitialInitial means beginning or at the start. In medicine, it can refer to the first symptoms of a disease or the first phase of a treatment process. trials with experimental vaccines against certain bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. that commonly cause abscesses have shown promising results. These vaccines could represent a preventive measure against the development of pus-filled abscesses in the future.

The use of probiotics as a supportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. in the treatment of infections that cause pus formation is also being investigated. Probiotics could help restore the microbial balance on the skin and in the body cavities of cats, which could support healing and reduce the rate of relapse.

In addition, research is being conducted on the development of new wound management techniques that are specifically tailored to the needs of cats. These techniques include the use of special bandages and ointments that promote healing and prevent infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. Such innovations could revolutionize the treatment of pus-filled wounds and shorten recovery time.

The role of nutrition in the preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. and treatment of infections that lead to pus formation is also being explored. Some studies suggest that a balanced diet rich in essential nutrients can strengthen the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. and reduce susceptibility to infections. Future research could develop specific dietary recommendations for cats that are prone to such infections.

In diagnostic research, new technologies are being developed to identify the causes of pus formation more quickly and precisely. Advances in molecular diagnostics could make it possible to identify the specific bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. that cause an infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. within a few hours, allowing for the immediate initiation of the most appropriate therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions..

Another aspect of the research is the investigation of environmental factors that can lead to the development of infections that cause pus formation. This involves examining how factors such as hygiene, stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being., and exposureExposure refers to the Contact with or subjection to certain substances, environmental factors, or pathogens. In veterinary medicine, this can include Contact with toxins, allergens, or infectious agents that can cause health problems in dogs and cats. to other animals can affect the risk of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. Measures to improve housing conditions could be crucial in reducing the frequency of infections.

Research on the discharge of foul-smelling pus in cats is crucial to improving the quality of life of cats and optimizing treatment outcomes. Advances in this area will not only benefit individual cats, but also help to promote the overall health of cat populations.

Frequently asked questions

What is foul-smelling pus in cats? Foul-smelling pus is a thick, often yellowish or greenish liquid that can leak from an infected wound or an abscess. The unpleasant odor is caused by the decomposition of tissue and the activity of certain bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease..
What causes foul-smelling pus in cats? Foul-smelling pus is often caused by bacterial infections that lead to abscesses or infected wounds. These infections can result from bites, scratches, or other injuries that become colonized by bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease..
How do I know if my cat has pus? Pus can be recognized by swelling, redness, and a foul-smelling liquid that comes out of a wound. Your cat may also show signs of pain or discomfort, such as licking the affected area or lameness.
Is pus dangerous in cats? Yes, untreated pus can lead to serious health problems, including systemic infections that can be life-threatening. It is important to treat pus quickly to avoid complications.
How is pus treated in cats? Treatment typically involves cleaning the infected area, administering antibiotics, and possibly draining the pus. In severe cases, surgery may be necessary to clean the infected area.
Can I treat pus in my cat myself? It is not recommended to treat pus in your cat yourself, as improper handling can worsen the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. A veterinarian should monitor the treatment to ensure that the correct therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. is applied.
How can I prevent my cat from developing pus? To prevent pus, keep your cat indoors or supervise it outdoors to avoid injuries. Practice good hygiene by keeping wounds clean and regularly checking your cat’s health.
What role does nutrition play in preventing pus? A balanced diet can strengthen your cat’s immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body., which can reduce susceptibility to infections. Talk to your veterinarian about appropriate nutritional plans that support your cat’s health and resilience.
Can stress affect the formation of pus? Yes, stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. can weaken the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body., which can increase susceptibility to infections and the formation of pus. A stress-free environment can help maintain your cat’s health.
Should I see a veterinarian if I notice pus? Yes, it is important to see a veterinarian if you notice pus in your cat. The veterinarian can make an accurate diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and initiate appropriate treatment to protect your cat’s health.