If you have a cat, it’s very likely that you have first-hand experience with hairballs or trichobezoars, if you want to use the scientific name. While the hairball is a well-known phenomenon, the science around it isn't very developed, which leaves us, cat guardians, wondering what is normal or not.
In this article, we will see what hairballs are and their causes, as well as how concerned you should be if your cat regularly throws up hairballs. Finally, we will investigate the possible remedies in the case of hairballs.

What are hairballs?

As you very well know, cats groom themselves by licking their fur with their tongue. As their tongue is covered in hard, keratinized papillae called barbs, they ingest some hair while they groom. Because hair is not digestible, the hair has to pass through the digestive tract and be excreted in the stools. However, the ingested hair can end up forming a fur ball in the stomach, and if it gets too big to pass through the pyloric sphincter (the exit of the stomach), the cats will have no other option than to vomit the hairball. [2]
Signs that your cat is trying to get rid of a hairball include coughing, vomiting, and retching. [3]
In addition to being a nuisance and uncomfortable for the cats, hairballs can sometimes block the digestive tract, resulting in an obstruction in various parts of the digestive tract such as the intestine, the esophagus, or even the nose. These obstructions lead to multiple symptoms such as abdominal pain or refusing to eat. In this case, the treatment will often be surgery or an endoscopy to remove the hairball (in one case report, a hairball was dissolved using Coca-Cola administered directly in the stomach). However, we don’t know how common these complications are or if they are rare occurrences. [2][4][5][15][17]

What are the risk factors?

There are two main risk factors for hairballs: excess hair ingestion and altered gastrointestinal motility. [2]

Excessive hair ingestion

Longhair cats are more likely to have hairballs than shorthair cats, as their fur is longer and they ingest more hair when grooming. The risk also increases for long-haired breeds with thick fur coats. [1][6][18]
Other risks include any condition that will increase the grooming behavior of cats, such as stress, flea infestation, or itchy skin. [2]

Altered gastrointestinal motility

Another hypothesized cause is a lack of contraction in the stomach to empty its contents. In fact, without these contractions, the hair won’t pass through the digestive tract. This altered gastrointestinal motility could be a sign of a disease such as inflammatory bowel disease. [2][7]

What’s a normal hairball frequency?

Despite how common hairball issues are, there isn’t any study on hairball frequency in cats, so it’s hard to determine what a normal frequency is. Most data we have are from the personal experience of veterinarians in clinics, and the norm could be between a few hairballs a year to one or two hairballs a month. In a study on older cats, 77% of cat owners reported seeing hairballs in the vomit of their cats, and 24% of the cats were vomiting at least once a month. [16]
Some studies also noted that in the case of chronic gastrointestinal diseases such as food intolerances or inflammatory bowel diseases, hairballs were a common symptom. However, other veterinary professionals consider that it could be a normal physiological process.
Rather than focusing on the frequency of hairballs, a better indication would be to monitor changes in what is “normal” for your own cats, as well as the presence of other symptoms such as weight loss or lack of appetite. [12][18]

The chicken or the egg

Based on what we know about the relationship between hairballs and gastrointestinal diseases, it appears that hairballs might cause gastrointestinal problems, but it's also possible that gastrointestinal diseases lead to hairballs. Therefore, in individual cases, it's often a 'chicken or egg' dilemma, where it's not clear which issue came first. [12][18]

Hairball remedies

If the hairball situation is linked to a gastrointestinal disease, the priority should be the management of the disease, as this should reduce the amount of hairballs. In that case, you should explore therapeutic options with your vet.

Reduce the amount of ingested hair

You can reduce the amount of ingested hair by brushing your cat daily to get rid of the loose hair. In the most extreme cases, and particularly for longhair cats, shaving your cat in a lion cut or on the belly may be advised. [2][6]
To prevent any flea infestation, be sure to be up to date with flea prevention.

Dietary approach

Fibers

High-fiber diets are often used to reduce the incidence of hairballs, however, studies on the efficacy of high-fiber diets are somewhat inconsistent. None of the studies investigated directly the number of hairballs vomited. Some relied on reports by owners of symptoms associated with hairballs, such as coughing, vomiting, or retching, while others investigated the amount of hair excreted in the feces.
Beet pulp fiber, a type of soluble fiber, didn’t show any efficacy, nor did miscanthus grass, a type of insoluble fiber.
Both sugarcane fiber and cellulose were effective in one study but ineffective in a subsequent study.
Psyllium, associated with slippery elm bark or cellulose, could be effective.
The hypothesis to explain the efficiency of fiber to reduce the frequency of hairballs is that fibers increase gastric motility, which helps to push the hairs out of the stomach before hairball formation.
While many commercial diets are marketed as reducing the incidence of hairballs, there aren’t any published studies on these diets. Some brands, such as Royal Canin or Purina, claim to have conducted internal studies, but none are published or publicly available.
So, if your cat is prone to hairballs, you can try a diet high in fiber, or add fiber to their diet; however, it’s not a guaranteed solution. [6][8][9][10][13][14]

Enzymes

A recent solution investigated in a study is the feeding of protease enzymes that degrade the hair, thereby preventing the formation of hairballs. This could be effective in combination with a high-fiber diet. [11]

Egg yolk lecithin

Egg yolk contains lecithin, which is a source of choline. Choline is a vitamin necessary for the synthesis of acetylcholine, a compound particularly important for the contraction of gastrointestinal muscles. As we have seen, one of the hypotheses for the cause of hairballs is a lack of gastrointestinal motility, which makes the supplementation of choline an interesting option. [19]
Another way lecithin could help is that it acts as an emulsifier, binding fat and water together. By binding to the fat in hairballs, it could help break them down.
As one of the richest sources of choline, regularly feeding chicken or quail egg yolk might help with hairballs. However, for a cat prone to hairballs, feeding egg yolk lecithin directly might be more helpful. There isn’t any study on the efficacy of egg yolk lecithin, but it is worth a try if other solutions aren’t working for your cat.
I would recommend starting with less than a capsule and progressively increasing to one or two capsules a day.
My experience with egg yolk lecithin has been quite positive. After several months of tests with one of my Norwegian Forest cats prone to regular hairballs, it reduced the frequency from weekly to about once a month. I found that one capsule (300 mg) a day was an effective dosage, and this option worked best for her, while fiber was ineffective.

Lubricants

Occasionally, when your cat is in discomfort, using lubricants in the shape of mineral oil such as flavoured petroleum jelly can help an existing hairball pass through the digestive tract.
However, this approach does not prevent hairballs but only assists when they have already formed. [2]

To conclude, it’s difficult to confidently say whether regular hairballs are a normal or concerning phenomenon. However, it appears that very frequent hairballs, especially when associated with other symptoms such as lack of appetite, could be indicative of gastrointestinal disease.
Regarding hairball remedies, some options exist, but keep in mind that studies are lacking, so take them with a grain of salt. Don’t hesitate to experiment to find what works for your specific cats.

Sources

[1] Kim, H. S. et al. (2019) “Effects of coat length and faecal hair removal on measured nutrient digestibility in cats.”, Journal of feline medicine and surgery, 21(4), pp. 379–386.

[2] Cannon M. (2013) “Hair balls in cats: a normal nuisance or a sign that something is wrong?”, Journal of feline medicine and surgery, 15(1), pp. 21–29.

[3] Beynen, A. C., Middelkoop, J. & Saris, D. H. (2011) “Clinical Signs of Hairballs in Cats Fed a Diet Enriched with Cellulose.”, American Journal of Animal and Veterinary Sciences, 6(2), pp. 69-72.

[4] Haynes, K. J., Anderson, S. E., & Laszlo, M. P. (2010) “Nasopharyngeal trichobezoar foreign body in a cat.”, Journal of feline medicine and surgery, 12(11), pp. 878–881.

[5] Kottwitz, J., & Munsterman, A. S. (2013) “Pyloric trichobezoar in a Canadian lynx (Lynx canadensis).”, Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians, 44(4), pp. 1111–1114.

[6] Weber, Mickaël et al. (2015) “Influence of the dietary fibre levels on faecal hair excretion after 14 days in short and long-haired domestic cats.”, Veterinary medicine and science, 1(1), pp. 30–37.

[7] Norsworthy, Gary D et al. (2013) “Diagnosis of chronic small bowel disease in cats: 100 cases (2008-2012).”, Journal of the American Veterinary Medical Association, 243(10), pp. 1455–1461.

[8] Dann, J. R., Adler, M. A., Duffy, K. L., & Giffard, C. J. (2004) “A potential nutritional prophylactic for the reduction of feline hairball symptoms.”, The Journal of nutrition, 134(8 Suppl), pp. 2124S–2125S.

[9] Loureiro, B. A. et al. (2014) “Sugarcane fibre may prevents hairball formation in cats.”, Journal of nutritional science, 3, e20.

[10] Donadelli, R. A., & Aldrich, C. G. (2020) “The effects of diets varying in fibre sources on nutrient utilization, stool quality and hairball management in cats.”, Journal of animal physiology and animal nutrition, 104(2), pp. 715–724.

[11] Miltenburg, T. Z. et al. (2021) “Effects of combined use of keratinolytic enzymes and sugarcane fibre on the hairball excretion in cats.”, Journal of animal physiology and animal nutrition, 105 Suppl 2, pp. 129–137.

[12] German, A. J., & German, A. C. (2013). Bad hair day. Journal of feline medicine and surgery, 15(1), 6–7.

[13] Loureiro, B. A., Monti, M., Pedreira, R. S., Vitta, A., Pacheco, P. D. G., Putarov, T. C., & Carciofi, A. C. (2017). Beet pulp intake and hairball faecal excretion in mixed-breed shorthaired cats. Journal of animal physiology and animal nutrition, 101 Suppl 1, 31–36.

[14] Antunes Donadelli, Renan & Aldrich, Greg. (2017). 236 Effect of grass as a dietary method to aid hairball control in cats.. Journal of Animal Science. 95. 116. 10.2527/asasann.2017.236.

[15] Woerde, D. J., Hoffmann, K. L., Kicinski, A., & Brown, N. L. (2019). Oesophageal obstruction due to trichobezoars in two cats. JFMS open reports, 5(1), 2055116918823581.

[16] Dowgray, N., Pinchbeck, G., Eyre, K., Biourge, V., Comerford, E., & German, A. J. (2022). Aging in Cats: Owner Observations and Clinical Finding in 206 Mature Cats at Enrolment to the Cat Prospective Aging and Welfare Study. Frontiers in veterinary science, 9, 859041.

[17] Wilson, S., Dobbins, D., Kawalilak, L., & Parambeth, J. C. (2023). Endoscopic administration of Coca-Cola for medical management of a wedged intestinal trichobezoar in a cat. The Canadian veterinary journal = La revue veterinaire canadienne, 64(8), 747–752.

[18] Pawenski, M., Smola, C. C., Dionne, T., & Larson, M. (2023). Histopathologic diagnosis and patient characteristics in cats with small intestinal obstructions secondary to trichobezoars. Journal of feline medicine and surgery, 25(9), 1098612X231196231.

[19] Zhao, F., Li, R., Liu, Y., & Chen, H. (2023). Perspectives on lecithin from egg yolk: Extraction, physicochemical properties, modification, and applications. Frontiers in nutrition, 9, 1082671.

Hairballs in cats: when should you be concerned and how to help?