The feline digestive system

The feline digestive system is similar in form and function to the canine digestive system. However, there are some differences in their diet that account for variances in how they absorb and use energy, and how long their digestive process takes.

Cats are obligate carnivores, which means that in order to survive, they need a diet that is primarily made up of meat. They can eat carbs and fats, but their health will deteriorate if they don’t get enough animal proteins to maintain their energy, lean muscle, tendons and ligaments, fur, skin, nails, hormonal balance and many other body organs and systems. Despite around 10,000 years of domestication, there is little that has changed in their protein-dominant diet. Therefore, their digestive system is primed to ingest, digest, absorb and eliminate based on a meat-based diet.

Cats’ stomach pH is highly acidic – almost twice as acidic as humans’ stomachs – to help break down proteins faster and neutralise bacteria in the meat they consume. Dogs’ stomachs are slightly less acidic due to their omnivorous diet, but still more acidic than humans’.  

Let’s take a quick look at your cat’s digestive system: the organs it’s made up of, how it works, how you can help your cat’s digestive system to remain healthy, the issues that could arise, and when to see the vet about any cat digestive ailments.

Organs of the feline digestive system

Your cat’s digestive system starts at her mouth and ends under her tail. The components and organs of the feline digestive system include:

  • mouth
  • oesophagus
  • stomach
  • liver (and gall bladder)
  • pancreas
  • small intestine
  • large intestine (colon)
  • rectum
  • anus

There are many complex organs involved in what we presume to be the simple process of eating and eliminating.

How does a cat’s digestive system work?

The aroma or anticipation of eating triggers the production of saliva in the cat’s mouth, which helps to moisturise her oral membranes and to lubricate the passage of food through the oesophagus and into the stomach.

When a cat has chewed up a mouthful of food, the contents she swallows are called a bolus. The bolus travels along the oesophagus and into the cat’s stomach. The muscles of the oesophagus contract involuntarily in a one-directional wave – a process called peristalsis – that carries the bolus through the digestive system.

When the bolus reaches the stomach, the digestive process begins, thanks to the presence of highly acidic gastric juices and digestive enzymes. The bolus is partially processed by the highly acidic gastric juices of the stomach as well as secreted digestive enzymes – this process can take a few hours – and the resulting chyme is gradually released into the small intestine. Chyme is more liquid than the bolus, and facilitates the further breaking down of nutrients, preparing them for absorption in the intestines. 

In order to help the process of fat absorption, the liver and gall bladder secrete bile into the first part of the small intestine (called the duodenum), which reduces the acidity of the chyme and aids the absorption of fat. The pancreas produces insulin to stabilise blood sugar and support the metabolism. It also secretes bicarbonate to alkalinise the digestible substances, and digestive enzymes to aid digestion.

In the next segment of the small intestine (the jejunum) the lining of this organ is covered in villi and microvilli – tiny ‘fingers’ that secrete digestive enzymes, absorb nutrients into the bloodstream, and prevent the absorption of waste materials. This is where amino acids (proteins) are absorbed into the bloodstream so they can be processed in the liver and used for physical energy and tissue and muscle maintenance in the cat’s body.

Peristalsis continues to push unabsorbed material through the last part of the small intestine – the ileum – that connects to the large intestine (colon). It is here that the last bit of moisture is extracted from the undigested material, which now accumulates and firms up as faecal matter. The colon moves this faecal matter into the rectum, out of the anus and in your cat’s litterbox. 

How long does it take for food to pass through a cat?

From top to tail, ingestion, digestion and elimination in a cat can take from 10 to 24 hours. Various factors will affect this timeline, such as the age of the cat, as well as its size, activity levels and overall health. The quality of the food is also important.

How do you take care of your cat’s digestive system?

Feed your cat high-quality, protein-rich food

As long as your cat is eating high-quality cat food that is rich in protein and moisture, she should be relatively healthy. Is kibble or wet food better for cats? It’s not a question of either/or, but rather the correct ratios of both. While kibble provides nutrient-dense feed and wet food provides additional beneficial moisture, it’s a combination of both wet and dry food together that will meet your cat’s need for a healthy diet. The important part is to ensure your cat is getting a balanced diet and that her caloric intake is meeting her nutritional needs. All cats need the highest quality food you can afford, to meet their energy needs and to support a healthy digestive system.

Make sure your cat is hydrated

Wet food is more easily digestible, especially since cats get more hydration from wet food, and it makes it easier for them to use the litterbox more regularly. That being said, dry kibble is also good for your cat – just make sure she drinks enough water, and always ensure she has access to fresh, clean water. Some cats may seem like they don’t want to drink water or are not thirsty, but what they really mean is they don’t like stagnant water. In these instances, you may find your cat enjoys drinking from a running tap, a bespoke kitty drinking fountain, or even your indoor fish pond. Cats that don’t drink enough water are at risk of urolithiasis – or bladder stones.

Feed your cat a prebiotic

Prebiotics and fibre) are a good supplement to add to your cat’s food. It boosts the growth of good bacteria in the gut, which helps to balance the digestive processes. If your cat suffers from hairballs and other digestive upset, a prebiotic supplement can support better motility in the digestive tract to help move those problems along. 

Exercise your cat daily

As with humans, an integral part of good digestion in cats is physical activity. This stimulates the digestive system to improve its motility (moving food along the small and large intestines) and to actively extract nutrients from food in order to use the caloric energy. A sluggish, sedentary lifestyle is not good for cats’ digestive health at all – so whip out a wand toy, bouncy balls or even a laser light to get your cat moving! Make sure you encourage your cat to play a few times a day and have fresh water available to keep her hydrated.

Do cats have digestive problems?

Your cat’s digestive process is the foundation of her health and wellbeing, but it’s also the system most susceptible to problems. Whether it’s a genetic issue, something caused by stress, indiscriminate eating (especially when hunting outdoors), allergies, poisons or food sensitivity (among other causes), many digestive problems have similar symptoms.

How do you know if your cat has a digestive problem?

There will always be some obvious signs and symptoms when your cat’s digestive system is under attack – the two most obvious being vomiting and diarrhoea. A distended belly and/or constipation, fever, reduced appetite, abdominal pain and/or a change in behaviour can also indicate digestive distress.

Common digestive issues in cats

The many various organs in the feline digestive system present many different areas in the body where issues can arise. Here, we focus on the more common digestive issues that cats may experience:

  • Hairballs – Since cats spend a large portion of their day grooming, it’s safe to assume they are going to swallow some of their groomed fur. Usually this fur can pass safely through their digestive system, but sometimes too much fur collects in the stomach and is vomited up. For cats that regularly experience hairballs, there is prescription cat food for hairballs that helps them to ingest and safely pass their excess fur. Regularly grooming your cat can also help the excess fur to not collect in your cat’s digestive tract.
  • Indiscriminate eating – Some cats will eat dodgy food from the garbage, a dead bird or rodent in the garden, or consume table scraps. These items may cause your cat to have an upset stomach – from mild to severe – so keep an eye on what your cat is consuming. Also make sure your cat has regular meal times so she doesn’t need to scavenge.
  • Stress – Most cats may seem indifferent to the life stressors around them, but when cats do suffer from stress, it can affect their appetite as well as their digestion. Stressors may include changes in the household, a new pet, your sudden absence, or loud experiences like thunder and fireworks. To help your cat with preventable stress, consider using a pheromone product a few weeks before a stressful event (such as moving house or adopting a new pet). Speak to the veterinarian if you suspect your cat may be suffering from stress, as she may be at risk of more serious conditions such as dehydration and weight loss.
  • Inflammation in the digestive tract – From gastritis (stomach) to enteritis (intestines) and pancreatitis (pancreas), cats may experience infection and inflammation anywhere in their digestive tract. Veterinarians don’t always know what causes this inflammation, but often food allergies and sensitivities are to blame. Medication, long-term dietary changes and supplements can help to restore balance and prevent future flare-ups.
  • Internal parasites – Grooming, exploring (and subsequent contact with faeces), hunting – these are all cat activities that can introduce parasites, viruses and bacteria to a cat’s digestive system. Internal parasites like roundworm, tapeworms, hookworm and whipworm can all be prevented by regularly deworming your cat and limiting her roaming. An overgrowth of intestinal parasites can have a negative effect on your cat’s digestive health, so it’s important to keep an eye on your cat’s whereabouts and ensuring she has regular vet check-ups.

There are many different causes of digestive upset in cats. If you are concerned about your cat’s vomiting, diarrhoea, lack of appetite, lethargy or any uncharacteristic behaviour, rather make an appointment with the vet to get her checked out.

When should you see a vet about a cat’s digestive system?

A single bout of vomiting or diarrhoea is relatively normal in most cats, and is a normal physical reaction to a toxin or substance your cat is sensitive to. But if your cat continues to vomit and show signs of digestive distress, treat it as a veterinary emergency. Cats can quickly become dehydrated from continuous episodes of watery diarrhoea, and if you see any blood in their stool, this could be a sign of a much more serious condition.

Similarly, chronic constipation can also have a number of simple or serious causes (such as inactivity in obese cats, or dehydration from kidney disease). If you notice that your cat is struggling to pass stool, rather take her to the vet before it becomes a medical emergency.

If your cat simply appears to not be acting like her usual self and her eating and elimination seem to be affected, make an appointment with the vet… just in case.


This brief overview of the feline digestive system, its form and functioning, shows just how important it is to look after your cat’s eating and elimination habits. As part of a carefully calibrated collection of systems that make up Your Cat, the digestive system has a direct influence on the optimal functioning of those other systems too. We will cover those in future articles, so check back regularly to learn more about your cat’s body and how it works.

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