Cat Reading Topics
Prevention of Feline Constipation

Prevention of constipation addresses the retention of water in the poop one way or another. This theme has been discussed several times and we come back to it again. Water makes the difference between a hard stool and a soft stool. Prevention of constipation means to ensure water retention in the stool, using appropriate methods which benefit the cat in various ways.

The unique sensitivity of cats as a species means any plan, whether short or long term, must be especially safe. Each new research study about cats seems to reveal more about their uniquenesses. Cats are strong. tough little creatures and yet they are very sensitive to diet, medications and household chemicals which may be safe for other species.

Treatment for a cat with a chronic condition needs to be ongoing. We want to prevent constipation, not chase it. A cat with chronic tendencies needs a consistent, thoughtful, safe and effective plan to treat and prevent constipation. While the remedies discussed in Acute Treatment can be helpful and some cats may need their ongoing assistance, constipation is not the result of lack of glycerine or stool softeners.

Other healthy cats in the house may have those 'occasional bouts of irregularity' so understanding the digestive tract and constipation prevention can be helpful for them also.

It is not sufficient to see poop in the litter box, we want to support a healthy gut environment.



Canned Cat Food 

Diet is the foundation of health, though not the only factor. Genetics plays a role, as does the cat's life style and exposure to environmental influences.

The details of feline nutrition are outside the scope of this website but health, including gut health, cannot be maintained without good nutrition. Cats have unique nutritional requirements, requirements which differ from humans or dogs or other species. However, the components of the cat's diet do not come from another planet, they are the same components of food which are familiar to us all, the same three pillars of diet – protein, fat and carbohydrate – just as they are for other species including our human selves. Cats require different ratios among those three than another species does but those three pillars are still the foundation of a cat's diet. The sources which fulfill those three pillars need to be selected somewhat differently for cats. For instance, cats require that their protein needs be met primarily by animal rather than plant sources, especially to supply adequate taurine, an amino acid which cats do not synthesize well for themselves. But it is protein, not some peculiar and unique need, that is being met.

Some opine that cats are unable to digest carbohydrates. If cats had not evolved with the ability to digest carbohydrates, the feline pancreas would not produce enzymes to digest carbohydrates and the feline pancreas does produce those enzymes. Cats do not produce salivary amylase but they do produce pancreatic amylase. Whole natural foods, including a mouse, are a mix of protein, fat and carbohydrate. The word 'carbohydrate' is a technical term in nutritional language; it is not synonymous with 'veggies' or 'grains'.Kitten

The question is not whether cats can digest carbohydrates, they can. The question is, what are appropriate carbohydrate sources for cats and what ratio is appropriate in their diet. We often read that cats do not require carbohydrates, which is true from one angle, cats themselves can manage without carbohydrate content in the diet. But not requiring does not mean cats are unable to digest carbohydrates.

Because cats utilize protein and fat so well to run and support their bodies and maintain their blood sugar levels, little to nothing is left over for the gut bacteria when the diet consists solely of protein and fat. The cat's native diet of mouse and other small prey was not just protein and fat; a mouse offers about three percent carbohydrate and the mouse digestive tract contains some plant material. Something needs to be included in the diet for the cat's gut bacteria, some form or part of plant material. The chapter Gut Bacteria and Fiber covers the benefits in some depth.

If only protein leftovers are available for gut bacteria to ferment, the more pathogenic bacteria benefit at the expense of the beneficial gut bacteria. Those protein leftovers come from shed gut wall cells and recirculating waste products from protein metabolism as well as any undigested dietary protein.

Keeping the beneficial bacteria populations high means they can convert the nitrogenous (protein) waste products into themselves, into more friendly bacterial bodies made of protein, which prevents the more toxic protein waste products from harming the gut wall. Better the friendly bacteria proliferate than those who are less desirable.

The point of fiber is that it is not digestible by the eater, whether that eater is a cat or a human, and so the undigested fiber remains in the digestive tract and flows on to the gut bacteria waiting in the wings. The parts of the included plant material that are digestible will be digested and utilized by the cat herself and, since cats have low dietary carbohydrate requirements, what to include is more critical for cats than for us omnivorous humans who can safely eat a much wider variety of plant foods in greater quantity.


Fiber or Prebiotics

Cat and Grass Can

The common term used for fiber naturally contained in food is dietary fiber. Fiber sources such as psyllium, FOS (fructooligosaccharides), inulin, beet pulp fiber, chicory root extract, etc. are called functional fibers. The dividing line is not all that clear since functional fibers may be extracted or concentrated from foods or may be synthesized.Kitten

Fiber is termed a prebiotic because it feeds the probiotics which is another word for gut bacteria. The term 'prebiotic' is usually reserved for functional fiber products. Few of us eat our baked squash or dark green leafy vegetables and then announce we just ate some prebiotics.

Ideally the chosen diet provides adequate and suitable fiber content but some cats may need additional help.

Fiber sources should be appropriate for cats and feed the beneficial gut bacteria without overfeeding them.

Cats, or rather their gut bacteria, do better with low-to-moderately fermentable fiber sources. Commercial cat food companies have access to fiber sources which we may not have. Research has shown that beet fiber and rice bran are good fiber sources for cats; they preferentially feed the beneficial gut bacteria and are not highly fermentable so do not risk bacterial overgrowth. Note that rice bran is a source of phosphorus if limiting phosphorus is necessary for your cat. There are about 11 milligrams of phosphorus in 1/8 teaspoon of rice bran though not all the phosphorus is bioavailable. All foods contain some phosphorus.

Guar gum is a common fiber source in commercial canned cat foods and in one study was more highly fermentable than other choices such as beet fiber and rice bran. Some fiber sources such as cellulose and psyllium starve the beneficial bacteria.

Many of us now read the back label of cat food, to choose cat food more carefully, but the type of fiber listed is still an orphan topic. It should not be, fiber is equally important in the dietary scheme even if it does not feed the cat directly.


Dietary Fiber

  • Pumpkin or Other Winter Squash – A traditional vet recommendation and a good one, plain unspiced canned pumpkin can help relieve either constipation or diarrhea as it normalizes the situation. The beneficial gut bacteria, when properly fed, are good at normalizing the bowel environment. Some cats report that Libby's plain canned pumpkin is the preferred brand but canned pumpkin does not agree with all cats. Baked winter squash can be fed and your cat may have preferences as to type of squash, or baby food winter squash can be used. Use small amounts mixed into several of the daily meals, a small amount being 1/4 to 1/2 teaspoon. Then monitor the results. Remember this is food for the gut bacteria, not the cat himself. If using canned pumpkin, freeze the can contents in ice cube trays, pop the frozen cubes into a freezer container, then thaw a cube at a time in a little glass jar in the fridge. Although cats are unable to convert the beta-carotene in orange vegetables to Vitamin A as humans can, they nevertheless utilize beta-carotene for their own health purposes.Kitten
  • Green Beans – Many cats like green beans, either home cooked, canned or baby food green beans. Some cats enjoy fresh raw green beans. Again, use small amounts mixed into several of the daily meals or offered separately at mealtimes.
  • Peas – Many cats also like peas which can be used in similar fashion to pumpkin/squash and green beans.
  • Slippery Elm Bark Powder – Familiarly called SEB, slippery elm bark is an old folk remedy for digestive problems. SEB has a reputation of being soothing to mucous membranes, which as we remember line any organ that has a direct connection to the outer world. SEB also contains fermentable fiber. There are two ways of using SEB, as a syrup and as the powder. SEB powder can be purchased from the bulk herb section of a health food store and an ounce or two goes a long way. Capsules of SEB must contain flow agents in order to get the capsules filled, to keep the powder from flying to the ceiling, so purchase bulk powder if you can. To provide fermentable fiber, use very small amounts of the powder in several meals. Remember this is dry powder so more concentrated than the fiber sources above. Start with 1/16 teaspoon or less and monitor results. To make the syrup, sprinkle a teaspoon of the powder over a cup of cool water in a little saucepan. Let the powder sit until it is wetted, this will avoid lumps to stir out. Then heat over medium heat, stirring the while, until the syrup is translucent and thickened a bit. It will thicken more as it cools. Store in a clean lidded glass jar in the fridge. Of course these amounts can be halved and there is no precise recipe, you can adjust the amount of powder per measure of water. SEB syrup keeps about a week in the fridge as long as the contents have not been contaminated by unclean utensils. Since it is easy to make, it is better to dump if there is any question and to mix up a new batch. Give 1 or 2 ml two or three times a day by Grassmouth or mix into food.
  • Grass – Growing 'cat grass' indoors has become quite popular, for those cats who have no outdoor access, lack access to safe grass outdoors, or experience long grassless winters. Grass contains fiber, not only in the grass itself but in its juice. Cats know a thing or two. Grass growing kits are widely available but for the definitive site on growing your own cat grass, google for "weird stuff we make catgrass," for the cats!.
  • Catnip – While catnip is not usually a daily event in cat lives and we do not add it to meals as a fiber source, nor is every cat genetically predisposed to appreciate catnip, catnip nonetheless contains fiber. In addition, catnip has a historic reputation as helpful for digestive upsets in humans, catnip tea in the human case. Part of the lore of catnip is its relaxant effect on the bowel. Source dry catnip with as much care as you would cat food or consider growing your own, for cats to nibble fresh or for you to dry to offer in off season. Select a mature sturdy plant from a nursery, one that can hold up to the assault of eager cats, or be prepared to protect it until it grows up. Catnip, whether dry or fresh, retains its properties but there is a difference in quality among the various producers of dry catnip. Since cats eat catnip as well as roll in it, you want a good source.


Changes to the diet or routine of a cat should be made gradually, to allow the cat to adjust and to permit the digestive tract to adapt. Cats sometimes need a new item or routine to be introduced several times before they accept. A tiny smidge of pumpkin can be added to a meal, the amount on the end of a toothpick or fork tine, not to fool the cat but to introduce gradually. There is no advantage to trying to push the process and good reasons not to rush the process. Nothing given can be retrieved but the amount can be increased tomorrow. Monitor the cat and the litter box during this process. These fiber sources are not systemic medications which means there is no precise dose nor is each cat eating the same diet with exactly the same other fiber sources.

Although I have read no research to confirm this idea, I think rotating these extra fiber sources may be a good plan. We have all heard that old cliche, that variety is the spice of life, and there is no reason to think otherwise for gut bacteria. Before cat food came in a bag or can, a cat ate a varied diet of creatures who ate varied diets which provided a varied diet for the cat's gut bacteria. If one dietary fiber source is introduced to a cat who seems to need extra fiber to prevent constipation and that fiber seems to 'stop working', try rotation.


Functional Fiber

  • Inulin, Psyllium, FOS (Fructooligosaccharides), etc. - Follow the manufacturer's instructions. Not all of these fiber sources are fermentable by cats, which starves their gut bacteria if serving as the only fiber source, and some are too fermentable or do not preferentially feed the more beneficial bacteria. As stated earlier, it is not sufficient to see poop in the litter box, we want to support a healthy gut environment. Research in the future, research specific to cats, will help refine the complex subject of functional fiber, of concentrated fiber sources extracted from foods.




Probiotics - A term for supplements of beneficial bacteria, probiotic supplements proliferate in the marketplace, for pets and for humans. Every choice advertises itself as the best choice. Research in this field truly is still in its infancy comparedKitten to how much there is yet to learn. Unless the cat has been on antibiotics or has some other specific health condition that indicates a need for probiotic supplements, my reasoning suggests that feeding appropriate fiber to the cat's resident gut bacteria makes more sense. After all, they already live there so are native residents, and may be suffering due to lack of feeding. Since half or more of the dry matter weight of the poop is gut bacteria, feeding the cat's own gut bacteria with suitable fiber makes sense from that angle, too. We could think of the gut bacteria as a chicken coop. It does no good to bring in ever more chickens if none of them is being fed. If you think your cat appears to require a probiotic supplement, work with your vet.

Recent research brings up the question as to whether live or killed probiotic supplements are better and safer. Those of us familiar with probiotic supplements have assumed that live bacteria are needed, we want to see so many million live organisms per acre stated on the bottle. While it is too early to know what research will eventually show, it is good to know there is a legitimate question as to the safety of live probiotics and may, surprisingly, show benefits from killed sources to which the gut responds. This suggests an additional reason for feeding the cat's own bacteria thoughtfully before reaching for an unnecessary supplement, and for working with one's vet when a supplement appears necessary.


Vitamins and MineralsVitamins and MInerals


Muscle needs good potassium blood levels to function properly, to respond to signals and intentions, to maintain oomph.

Nerves need B vitamins and adequate magnesium blood levels to transmit signals properly.Kitten

Nerve sheaths, the outer protective covering of nerves, need good body levels of Vitamin B12 to ensure nerve integrity, so that the nerves inside the sheaths are not vulnerable to exposure and do not 'short out' as it were. The usual form of supplemental B12, added to most commercial cat foods and supplements, is cyanocobalamin which requires conversion in the body to an active form. Cyanocobalamin is actually an artifact of the purification process when synthesizing Vitamin B12. The methylcobalamin form of Vitamin B12 does not require the same conversion and is now more readily available for purchase for cats who require supplemental Vitamin B12.

The entire family of B vitamins called B Complex are important to help maintain gut health and to prevent constipation. Vitamins are not nutrients, they are co-enzymes, that is they assist enzymes to do their jobs. Enzymes are not only involved in digestion, enzymes play a role in all metabolic functions and each enzyme is specific to its task. Without adequate B vitamins such as folic acid and Vitamin B12, enzymatic function suffers. First to suffer are those areas of the body with faster cellular turnover such as the gut wall and the blood components. If gut barrier function is reduced, the body itself is more vulnerable to trouble and the enteric nervous system is at risk of damage.

Of course general nutrition is important which a good diet supplies in a balanced format. Extra vitamins and minerals seem to be added to everything commercial made for the cat, from treats to 'appetizers', and many humans who live with cats think that a cat needs a daily vitamin/mineral supplement in addition to the diet. Unless a cat tests deficient, is not eating well, or has a condition that requires extra supplementation, more is not better than enough and may be harmful. The B vitamins are water soluble and so more 'forgiving' as any extra can more easily be dumped into urine rather than accumulating in the body. Still unnecessary supplementation, above demonstrated or diagnosed need, is to be avoided.

Food itself is very nutritious. Before humans came along to invent supplements, every living being on earth was sustained by food, for millions of years, and despite dire warnings to the contrary, food is still nutritious. A stroll through the USDA National Nutrient Database is surprisingly reassuring, in a general sense, about the nutritional value of food items such as meats or the vegetables listed above for dietary fiber.

USDA Food Database

I have found that both diet and nutrition make more sense when I think of food as having had a previous life. While that is not always a comfortable mental process, it is nevertheless true that items we come to call food once had lives of their own, whether that was an animal life or a plant life, a chicken or a squash. Chickens and squashes have nutritional requirements of their own which are similar to ours in many ways even though they may use different tactics to meet those needs. Squash fruits do not need skeletons, they need strong cell walls to form a sturdy incubator for their seeds. Take a moment to check out 'squash, winter' at the link above, read the list of nutrients and realize that the squash plant was using potassium and magnesium and calcium and phosphorus and B vitamins and amino acids and lipids for its own nutritional agenda, just as we do for ours and cats do for theirs. Squashes go about their business quietly but they still have personal business which requires nutrition.Kitten

The listings at that site for the various food plants focus on nutrients of interest to us, the human eaters, but there is more to plants than what we humans find important for the dinner table. Unlike ourselves and our cats, plants are not able to sock a predator in the nose or run and hide so they developed various ways to protect themselves including thick hides, thorns, and chemical warfare.

If you would like to learn more about the complexity of plant chemistry, check out Dr. Duke's Phytochemical and Ethnobotanical Databases to understand why we need to choose plant sources more carefully for carnivorous cats than for omnivorous humans. We ate a large variety of plant foods and evolved with livers which are capable of detoxifying many more plant chemicals than cats can detoxify. Cats, who ate little plant material directly, depended on the livers of their prey species to do the detoxifying for them, then ate the prey. Either cats never developed the necessary hepatic pathways or lost them along the evolutionary trail. We need to select dietary plant material more carefully for cats.

Dr. Duke's Database


Osmotic Laxatives

If a change in diet or the addition of appropriate fiber to the diet is not enough to prevent constipation in a cat prone to constipation, osmotic laxatives can be helpful so they are included in this prevention chapter also. Consult with your vet for the best choice and dose for your cat.

  • Miralax – Miralax is polyethylene glycol, PEG 3350. The number 3350 describes its average molecular weight and distinguishes Miralax from polyethylene 300 or polyethylene 400, for instance. Polyethylene glycol is not ethylene glycol, more familiarly called antifreeze. Polyethylene glycol is also not propylene glycol, the alternative. It is polyethylene glycol. The differences in chemical formulas matter. We would be pleased to drink a cool glass of H2O (water) but should not be pleased to drink H2O2 (hydrogen peroxide) even though there is only a single atom of oxygen difference per molecule. Miralax retains water in the bowel and/or the stool. Miralax is a powder which readily dissolves in water or wet food. A typical starting dose for a cat is 1/8 teaspoon total daily, divided into several smaller portions over the course of the day, but your vet should advise for your cat. There is a warning on the Miralax bottle for kidney patients which unnerves many with cats with kidney disease. That warning is present not because Miralax is harmful for kidney patients, it is not harmful. Now that Miralax is an OTC product, no longer requiring a prescription, it is a caution for humans with a tendency to self-diagnose and self-treat for months without consulting with a doctor, humans who think if a little is good, a lot is better. Provoking the Kittenequivalent of diarrhea by use of any laxative causes water and electrolyte loss which can lead to dehydration which is more risky for those with kidney disease than for healthy individuals. Proper and appropriate use of Miralax is safe for cats with kidney disease, with emphasis on proper and appropriate, with a normal stool as the goal.
  • Lactulose – Lactulose is an indigestible sugar that acts as an osmotic laxative. In humans it apparently is a fermentable fiber for the gut bacteria. I've read that it is for cats, I've read that it isn't. The byproducts of the gut Osmotic Laxativesbacteria help regulate pH in the colon, and it is the pH that determines how much water will be retained in the stool. Lactulose alone influences the pH of the bowel, it has the necessary slight acidifying effect to cause water retention, whether or not it is fermentable by cats. Lactulose requires a prescription from the vet who will also prescribe the recommended starting dose for your cat. Lactulose, like Miralax, is a dose-to-effect drug with a normal stool as the goal.

Concerns are often expressed about cats with chronic constipation, such as cats with kidney disease, that use of an osmotic laxative will dehydrate the cat because these products draw water to the bowel or hold it in the stool. If producing a normal stool puts a cat at risk of dehydration, more is wrong than constipation and sometimes what is wrong is the human reasoning. Dehydration is not a recommended treatment for constipation! The amount of water needed to normalize the stool in response to an osmotic laxative is the same amount of water by any other method including diet and dietary fiber. This does not mean that these osmotic laxatives should not be treated with respect, of course they should be used conservatively and appropriately. But producing a normal stool by use of an osmotic laxative should not dehydrate a cat.

Again, all changes for the cat should be made gradually, to allow the cat to adjust and to permit the digestive tract to adapt. The digestive tract is remarkably adaptable, within certain parameters, but it takes time to adapt.

Remember, increasing Miralax or Lactulose increases the amount of water in the bowel/stool. If the stool is too soft, reduce the amount of laxative. Osmotic laxatives are dose-to-effect drugs and, unlike most medications, we can monitor the effects in the litter box.

Paw Print Two

Here, in summary, are the CliffsNotes for this website:

  • inside the gut is not inside the body
  • the difference between a hard stool and a soft stool is water in the stool
  • prevention of constipation involves water one way or the other, water retained in the poop, not necessarily in the cat
  • since they are on our side, we honor gut bacteria with suitable fiber
  • there is more to treating and preventing constipation than seeing poop in the litter box, we want to support and maintain gut health
  • cats are quirky, sensitive and astonishing and we love them


You can always browse Review for pinning tails more securely on the donkey. Review gathers all the Quick Reviews in one place.

The Glossary helps to clarify the various terms used in the website and is also a helpful review.





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Sitting Cat Looking Up at Chapter Title
The First Lesson
Gut 101 – Full Version
Gut 101 – Condensed
Gut 102 - Full Version
Small Intestine
Large Intestine
Gut 102 – Condensed
Gut Bacteria and Fiber
What Goes Wrong?
Acute Treatment
Saline Laxatives
Stimulant Laxatives
Lubricant Laxatives
Stool Softeners
Osmotic Laxatives
Fiber or Prebiotics
Vitamins and Minerals
Osmotic Laxatives
Contact and More