What this means
Gas forms when microbes in the gut ferment material that has not been digested, and also when a dog swallows air. That is why dogs that eat greedily often pass more. The amount of gas does not name a cause; what happens alongside matters more.
Note when there is most gas: after meals, at night or after certain titbits or human food, whether it smells very strong, and whether the belly also gurgles, the stools change or your dog vomits. Also notice whether your dog is bright, shows any discomfort in the belly and whether its weight is steady.
Gas that appears suddenly with pain, a swollen belly or restlessness is not the same as a mild excess that has gone on for a long time. In the first case, do not wait.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your dog.
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Greedy eating and swallowed air
A dog that gulps food without chewing swallows air too, so there is more gas after meals. Otherwise your dog is bright and well.
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A food change or random scraps
A new food, leftovers from the table or things picked up outdoors can cause extra gas. It usually settles once that stops.
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Too many bacteria in the small intestine
When the small intestine holds too many bacteria, more gas forms and the stools may turn looser. This usually keeps coming back.
About the condition: Small intestinal bacterial overgrowth (SIBO) -
Too few digestive enzymes from the pancreas
When the pancreas makes too few digestive enzymes, food is digested less well, so your dog may pass a lot of gas, lose weight and pass greasy, bulky stools.
About the condition: Exocrine pancreatic insufficiency (EPI) -
Allergy or intolerance to an ingredient in the food
A reaction to an ingredient can irritate the gut and cause gas and diarrhoea. Itching often shows up as well.
About the condition: Allergies (food, skin and environmental) -
Intestinal inflammation
Long-term inflammation of the gut can show as gas, a gurgling belly, diarrhoea or vomiting.
About the condition: Inflammatory bowel disease (IBD)
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- When there is most gas: after meals, at night or after certain foods
- Whether it smells unusually strong
- Whether the belly gurgles
- Whether the stools changed
- Whether your dog vomits or eats grass
- Whether weight and appetite are steady
When to book a routine visit
Book a visit if there is unusually much gas for more than a few days, if the stools, appetite or weight changed at the same time or if your dog seems uncomfortable. If any of the urgent signs above appear, go straight away rather than waiting for an appointment.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Small intestinal bacterial overgrowth (SIBO) Digestion and liver This is a condition in which too many bacteria, or the wrong kinds, take hold in the small intestine. They compete with the dog for nutrients and irritate the gut wall, so food is digested and absorbed less well. It can be the result of another intestinal or pancreatic problem, so a vet also looks for the underlying cause.
- Exocrine pancreatic insufficiency (EPI) Digestion and liver This is a condition in which the pancreas doesn't produce enough digestive enzymes, so food passes through almost undigested and the body misses out on the nutrients it needs. As a result, a dog can eat for two and still lose weight. A vet confirms whether it really is EPI with tests.
- Allergies (food, skin and environmental) Skin and coat An allergy is an overreaction of the immune system to substances that are essentially harmless, such as pollen, house dust mites, moulds, flea saliva or an ingredient in food. In dogs it shows up mainly in the skin and ears, and constant itching wears a dog down and can open the way to skin infections. More than one trigger can be involved at once, so finding the cause takes patience.
- Inflammatory bowel disease (IBD) Digestion and liver This is a long-term disorder of the digestive tract in which inflammatory cells build up in the wall of the stomach or intestine, so it becomes less able to digest food and absorb nutrients. The exact cause is not fully understood; an interplay between the immune system, gut bacteria and food is thought to play a part. Because many other digestive problems look much the same, a vet works out what is really going on with tests.
- Giardiasis Parasites Giardiasis is a gut disease caused by single-celled parasites called Giardia. A dog becomes infected by swallowing their cysts with water, grass or another dog's faeces. The parasites disturb the absorption of food, so the stools turn soft and the diarrhoea keeps coming back; a vet identifies the parasites from a stool sample.
Body systems: Digestion and liver Skin and coat Parasites