My Dog (Less Than 8 Years Old) is Coughing Up Phlegm or Mucus, but is Otherwise Acting Normal

This article was updated on September 13th, 2022

Your situation:
✓ Your dog is less than 8 years old
✓ Your dog has a wet cough (coughing up phlegm or mucus)
✓ Your dog doesn’t show other signs of illness
(If this is NOT your situation, click here)

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, 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.

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.

Most Likely Causes for a Wet Cough in an Otherwise Healthy 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. Kennel Cough / Upper Respiratory Infections

What it looks like:

✓ Dry “honking” cough
✓ Some dogs still have high energy
✓ Some dogs still eat normally

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.

This is what Kennel Cough Sounds like (Watch the video):

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.

2. Heart Disease

What it looks like:

✓ Dry or wet coughing
✓ Coughing after getting up
✓ Difficulty breathing / gasping
✓ Getting tired quickly or not feeling well

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.

This is an example of what coughing due to heart disease sounds like:

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

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.

3. Fungal Pneumonia

Though more common in some regions of the Untired States than others, fungal disease can also cause a wet cough in a young dog. Your dog may become infected with fungal pneumonia if they inhale spores of certain fungi such as Coccidiodes immitis, Aspergillus spp., Cryptococcus neoformans, or Histoplasma capsulatum. Fungal pneumonia is typically serious and should be treated right away.

4. Heartworm Disease

Heartworm disease is another possible cause of a wet cough in a young dog, especially if they are not receiving year-round heartworm prevention. Heartworm disease can become fatal as well and lead to severe disease of the heart and lungs if left untreated. All dogs should receive heartworm prevention according to their veterinarian’s instructions and be tested annually.

Disclaimer: Other medical conditions causing dogs to cough include cancer, endocrine disease, autoimmune disease, foreign material in the throat, and others. It is important to meet with your veterinarian to perform a full medical exam and ensure correct diagnosis and treatment.

8 Best Home Remedies To Help Your Coughing Dog

Our veterinarian Dr. Debra Eldredge – author of the best-selling book “Dog Owner’s Home Veterinary Handbook” – has compiled for us a list of the most effective home remedies to help coughing dogs:

1. Start with Simple Home Care: If your dog has discharge from his eyes or his nose, use a warm compress to soften the crusts and clean gently. A dab of vitamin E (puncture a capsule with a pin and squeeze out a drop) can help with a sore nose. Artificial tears drops or ointment can be safely applied to his eyes.

2. Use a Humidifier or Steam: Excessively dry air can cause coughing in dogs. If you have a humidifier, encourage your dog to rest in that area. 

3. Use a Teaspoon of Honey: People also often reach for honey when they have a cough. A teaspoon of honey in a cup of warm water may ease a short throat. This is not recommended for puppies (think about infant cautions) or for dogs with diabetes as it can interfere with glucose regulation.

4. Consider Limiting Physical Activity in Cold Weather: Very cold, dry air outside can stimulate coughing as well as dry air inside. Senior dogs don’t handle extreme cold well. Keep walks short and limited. 

5. Use a Non-Restrictive Harness Instead of a Collar: Be sure that you use a non-restrictive harness for walks. Do not walk your dog on a collar. The pressure on the trachea can stimulate more coughing.

6. Give your Dog a Quiet Place to Rest: Coughing can be exhausting. Make sure your dog has a quiet place to rest, away from active children or other pets.

7. Increase Hydration: It is important to support your dog’s hydration when he has a cough: coughing can increase his normal hydration needs. If your dog is not drinking enough water, consider trying homemade chicken soup, low or no sodium bouillon, or adding some juice from tuna canned in water or other meat juice flavoring (plain) to his water.

8. Over the Counter Cough Medication: Dextromethorphan is a common ingredient in human OTC cough medications such as Robitussin. It can be helpful for some dogs short term. This is an “off label” medication so you should check with your veterinarian about use in your individual dog. It is not recommended for dogs with liver problems or for dogs on a number of medications.

Continue reading: 8 Best Home Remedies to Help a Coughing Dog (Vet Advice).

Important: the home remedies mentioned here are only supportive ideas to help your dog with symptoms – they are not likely to help with the root cause. A visit to your veterinarian is important to help understand the root cause and define an effective treatment plan.

When Is Coughing Serious Enough to See Your Vet?

You might be wondering if your dog’s cough or gagging is serious enough to justify a visit to your veterinarian. It can be hard to know as an owner when a cough is serious enough to warrant veterinary attention.

A dog may occasionally cough to clear their throat or if something irritates them. That’s usually not a cause for concern. However veterinary attention is likely required if a cough:

• becomes persistent,
• lasts more than 2 days, or
• becomes more frequent or severe

Additionally, a cough is always serious if it comes with breathing difficulties, if your dog is generally unwell in themselves or if they are coughing up large amounts of phlegm or blood.

As a general rule, it may be ok to just monitor your dog’s cough at home, if your dog is still:

• bright in themselves and
• eating and drinking as normal

Since coughing can be a symptom of a serious ailment, it’s important to be cautious and take your dog to the veterinarian if you are unsure about what to do.

What Will the Vet Ask You

It’s important to be prepared for the basic questions your vet will want to ask about your old dog’s coughing or gagging. Being able to answer your vet’s questions will help improve diagnosis and ultimately solve the issue faster for your canine friend. Questions may include:

• How can you describe the cough? (choking, gagging, retching, gasping or throat clearing noise, etc?) – it may not even be a cough at all!
• Is the cough productive – i.e. does your dog bring anything up when they cough?
• Are there any other signs associated with the cough such as breathing issues or lack of appetite
• How frequent is the cough? Is coughing on a daily basis, several times per day?
• How long has coughing been going on?
• Does the cough appear to come more from the throat or chest?
• Does anything trigger the cough? Or does it happen in a specific environment?

How Will Your Vet Diagnose the Issue?

Your vet will start by taking a thorough history (see how to prepare for the visit below) and by performing a physical examination on your dog. They will pay particular attention to any abnormal heart or breathing sounds, the heart rate and rhythm and your dogs temperature. By using all of this information, they will then decide the best next course of action.

Sometimes your vet may opt to start a trial treatment plan and base the diagnosis on the response to medication. For example, in the case of kennel cough, anti-inflammatory medication is often all that is required and if your dog responds well then it’s likely that kennel cough was the cause.

However, if a heart murmur or abnormal heart rhythm is detected then a heart ultrasound scan and X-rays might be the next step. This will help evaluate whether or not your dog’s heart has signs of congestive heart failure such as thickening of the heart walls, inefficient heart valves or fluid build up within the lungs.

X-rays are a key tool in evaluating any dog that has developed a persistent cough. By taking an X-ray of your dogs chest and lungs, vets will be able to visualise the distribution of air within the lungs. A healthy dogs lungs should appear dark on an X-ray as they are full of air; the presence of any lighter coloured areas may indicate thickening within the lungs or even fluid build up. There are many different ‘lung patterns’ that can be identified on an X-ray that can point towards a specific diagnosis.

Related article: How to help your coughing dog at home:

8 Best Home Remedies to Help a Coughing Dog [Vet Advice]