My Old Dog is Coughing Up Phlegm or Mucus, but is Otherwise Acting Normal

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Any time your senior canine friend isn’t feeling well, it is concerning. Just like in humans, coughing is a common health issue. There are many different types of coughs. A cough that sounds “wet” or results in the production of mucus and phlegm, which is coughed up, is often termed a “productive” cough. This in itself is not a cause for grave concern, especially if your dog is still acting normal and feeling well.

When a dog is coughing, this is a sign that something is amiss in their respiratory tract. If this cough is accompanied by the dog feeling unwell, lethargic, or not eating, medical attention should be sought from a veterinarian immediately. However, if the coughing dog otherwise feels fine and is acting normal, the cough is likely due to a mild upper respiratory infection.

You should make an appointment to have the dog seen as soon as possible, but it is unlikely that it is an emergency.

Most Likely Causes for a Wet Cough in an Otherwise Healthy Senior Dog

When our pups get older, they may be more likely to have some conditions and diseases. The wet or productive cough in a senior dog is a great example of this. In a young dog, the most likely diagnosis is an upper respiratory infection. However, in older dogs, heart disease is vastly more common. The two most common causes of wet coughs in dogs that are feeling well include:

1. Heart Disease

Different breeds of dogs are more prone to certain heart diseases. However, the most common type of heart disease we see is dilated cardiomyopathy (DCM). This heart condition results in a “stretched out,” flabby heart that loses the ability to contract properly. This leads to sluggish blood flow and fluid buildup in the lungs and abdomen.

Heart disease tends to cause a wet or productive cough because of fluid pooling in the lungs. This occurs because the heart is not pumping efficiently. Often these wet coughs are observed more frequently in the mornings upon waking or after lying down.

Dilated cardiomyopathy, if left untreated, will likely progress into congestive heart failure. Catching the disease in its early stages is very important, so any old dog with a wet or productive cough should be seen by their veterinarian as soon as possible, even if they are feeling well, and the dog is otherwise acting normal.

There are treatments available to combat DCM and to ease congestive heart failure; however it cannot be cured. Depending on the severity of the condition when diagnosed, costs may range from a few hundred dollars to thousands.

2. Upper Respiratory Infections

Infectious respiratory diseases, including viruses and bacterial causes such as “kennel cough,” are extremely common. These infections typically cause a dry, “honking” cough but can also cause a wet, productive cough. In my experience, viruses such as canine influenza are more often associated with wet coughs.

Dogs may pick up the bacteria or viruses that cause these upper respiratory infections anywhere where they come into contact with other dogs. Common places are boarding and grooming facilities, vet’s offices, doggy daycare, and dog parks.

If your dog is feeling well and acting normally, they should be seen by their veterinarian as soon as possible. If the upper respiratory infection is caught and treated early, it is likely that they will feel better sooner and avoid serious complications. If bacterial, these infections may be treated with antibiotics, or medications may be given to ease clinical signs. Dogs may require anti-inflammatories, cough suppressants, or expectorants.

The cost to treat a mild upper respiratory infection varies widely depending on diagnostics and treatments needed. Typically, this trip to the vet will run anywhere from $100 to $500.

3. Other Causes

Of course, there are exceptions to this, and it is always important to get a proper diagnosis. Unfortunately, cancer, both primary lung and metastatic, is also high on the list for older coughing dogs.

Vet Tip: Record Your Dog While Coughing

Being able to describe your dog’s cough will aid in your veterinarian’s diagnosis. However, evaluating a cough and knowing if it is wet or dry, as well as coming from the upper or lower respiratory tract, can be difficult. If possible, I recommend video recording your dog while coughing and showing the video to your veterinarian.

How To Help an Old Coughing Dog at Home

Because your dog cannot talk and tell you what they are feeling, it is essential to have a veterinarian evaluate them whenever they develop a cough. There are many causes of dog coughs, and the treatments are varied. If left untreated, many conditions will worsen and may become life-threatening. The sooner your dog is seen and treated, the sooner they will be feeling better! You should not administer any over-the-counter medications to your pet, either human or veterinary, without permission from your veterinarian. These medications may be toxic, contraindicated in your specific dog’s situation, or even make the condition worse.


  • Dr Whittenburg, Hospital Director

    Dr. Jamie Whittenburg is a Veterinarian Director at 'Senior Tail Waggers' and Director and Owner of Kingsgate Animal Hospital, a full-service animal hospital in Lubbock, TX. She graduated from Kansas State University's College of Veterinary Medicine (DVM) and has over 17 years of experience working as a veterinarian & hospital director.

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Disclaimer: This website's content is not a substitute for veterinary care. Always consult with your veterinarian for healthcare decisions. Read More.

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