Gassy Dog

Gassy Dog!!

“OH MY!! What’s that smell?!”
“I think Buster farted!”
“Hahahaha. Sure, it was the dog.”
“Really. I think something is wrong with him.”
Does this conversation sound familiar?

The Science of Flatulence

Flatulence comes from an excess of gases in the intestinal tract. These gases may represent air that has been swallowed, gas produced in the biochemical process of digestion, gas diffusion from the bloodstream, or gases produced by the bacteria that populate the intestinal tract. Over 99% of the gases that pass from the intestinal tract are odorless; the gases with objectionable odors are typically those containing hydrogen sulfide.

Flatulence is a normal biological function. A surprising amount of air is swallowed with the simple act of eating and if this is not burped out, it must exit through the other end. The amount of air swallowed tends to be increased when dogs feel they must eat quickly or in the brachycephalic breeds who tend to breathe more by mouth rather than by nose. Swallowed air tends not to have objectionable odor.

The really stinky gases are produced by colon (large intestine) bacteria. Dietary fiber in pet food is not readily digestible by the pet’s own enzyme systems but is readily digested by the gas-producing bacteria of the colon. As these fibers are broken down, gases are produced. A diet heavy in fibers tends to favor these gas-producing organisms. The more supportive the intestinal environment, the more bacteria there will be and ultimately more gas will be produced.

What to do about it

The following are easy changes that can be made in the management of your pet:
• Feed smaller meals several times daily instead of one larger daily meal.
• Feed a mixture of dry and canned foods.
• Discourage rapid eating by placing an over-turned small bowl inside the pet’s regular food bowl.  Or order a specially made bowl with an irregular surface, that allows food to fall between the grooves. This prevents the pet from taking such a large mouthful and subsequently swallowing extra air…
• Avoid soy and peas in the diet.
• Avoid any treats containing milk, cheese or other forms of lactose.
• Avoid fresh or dried fruit treats. Although these are often low allergy and low calorie treats, if your dog has gas problems, you may need to find other alternatives.
• Change to a high digestibility/low residue diet. There are therapeutic diets sold at most veterinary offices that would be perfect. Ideally, rice would be the diet’s carbohydrate source.
• If possible, walk your dog within 30 minutes of eating so as to encourage passing gases outside.
• Avoid canned foods containing the texturing ingredient carrageenan.

Prescription Low Residue Diets

Changing to a low residue diet means that most of the nutrients of the food are digested and absorbed by the pet before they reach the colon where the gas-forming bacteria are. This means there will be less food for the gas-forming organisms, which will ultimately mean fewer gas-forming organisms and less gas formed. Sometimes just going through a case and/or bag of such a low residue diet solves the problem and the pet can return to a regular food afterwards. If necessary, the therapeutic diet can become the pet’s regular food.

Hypoallergenic Diets

Some dogs have problems with food allergies. If a patient is allergic to its food, they are more likely to have irregular bowel activity that promote excess gas production. Eliminating common ingredients like chicken, beef and corn can sometimes help. Limited ingredient diets like rabbit and potato, or duck and potato can sometimes alleviate the problem.

Sometimes Medication is Needed

A carminative is a medication that reduces flatulence. There is an assortment of available products, but unfortunately most are not helpful or even labeled for animal use. Changing the diet and ruling out actual intestinal disease are of primary importance in addressing flatulence. If further therapy is needed, the following products have some basis to suspect they might work:
Yucca shidigera supplementation

Currently this extract is labeled as a flavoring agent for pet food but it is also available as an oral supplement. Several studies have shown that it helps decrease the odor in flatulence.

Zinc acetate supplementation

Zinc binds to sulfhydryl compounds in flatulence ultimately serving to deodorize the gas.

Non-absorbable antibiotics

Such antibiotics serve to kill the gas-forming bacteria of the colon and may be helpful as long as their use is not ongoing.

Questionable Products


There are many ineffective probiotics being marketed so it is important to use one that has been shown to actually contain live cultures and that its cultures actually withstand stomach digestion so as to populate the small intestine with beneficial bacteria. It is unknown if this type of product would really help in flatulence as it is asking a great deal for such bacteria to travel all the way to the colon and attempt to displace the gas-forming resident bacteria. That said, there are several veterinary products that are felt to be reputable: Prostora® Proviable® and Fortiflora®. Fortiflora, Purina’s product, has been shown to be effective in reducing flatulence.

Activated charcoal tablets

These tablets are not likely to be effective as the charcoal-binding sites are filled on the journey from mouth to colon, and by the time the tablet gets to the gas-forming large bowel bacteria, it has essentially been used up.


This product may control the volume of gas produced, but not the odor. It is an antifoaming agent that reduces gas bubbles.

Pancreatic enzyme supplementation

In the absence of exocrine pancreatic insufficiency, it is unlikely that a patient would be helped by extra digestive enzymes. Furthermore, this treatment is relatively expensive for something that may only be helpful.

See your veterinarian!

Ultimately, there may be a combination of issues contributing to your gassy pooch. Keep your pet’s diet simple. Avoid people food. And see your veterinarian if the problem persists. Nobody wants a Dutch-oven from their furry housemate.


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