Coca-Cola has a small, well-documented niche in human gastroenterology and a more recent, less rigorous one in equine practice. A study from 2021 on Coca-Cola used to treat horses with gastric conditions has been picked up again and seems to be doing the rounds, with associated confusion and misinformation. In this study it was used to help dissolve certain gastric masses; not to treat ulcers. Confusing the two conditions is easy, which is why owners should not reach for a two-litre bottle.
Coca-Cola for bezoars in people
A phytobezoar is a compact mass of indigestible plant fibre in the stomach. Persimmon (diospyrobezoars) form particularly hard masses. In 2002 Ladas and colleagues reported nasogastric Coca-Cola lavage in a handful of patients. A 2013 systematic review by the same group collected 24 papers and 46 patients published between 2002 and 2012. Coca-Cola alone fully dissolved the mass in about 50% of cases; combined with later endoscopic fragmentation, it succeeded in 91%. Only four patients needed surgery. Ordinary phytobezoars dissolved more readily than persimmon bezoars. Typical protocols used 0.5–3 litres over 24 hours to several weeks, given as drinks or lavage.
The evidence of efficacy is modest. Most papers were single-case reports or tiny series. There was no randomised comparison with placebo or other solvents in the original review. Later work includes small prospective series and at least one randomised trial comparing cola drinking with endoscopic fragmentation; cola remains a cheap, low-risk first step that can shrink a mass enough for endoscopy or, in some patients, avoid it. Risks exist! Fragments can migrate and obstruct the small bowel even after apparent success. Bezoars themselves are often associated with gastric ulcers; cola is used despite that, not as ulcer therapy, and volumes are controlled.
The proposed mechanisms are low pH (phosphoric and carbonic acids, around 2.5–2.7), carbonation that mechanically loosens fibre, and perhaps mucolytic effects. Diet versions work; sugar is not required.
The horse study: useful but not high-quality
The largest equine paper is Witt, Hagedoorn, Kranenburg and van den Boom (2021): a retrospective review of 125 horses with gastric impactions seen at one Dutch clinic from 2003–2019. Horses that received nasogastric cola were discharged alive more often (48/58, 83%) than those that did not (24/67, 36%). Average time to resolution when recorded was 2.6 days. Friesians were heavily over-represented (31% of cases vs 9% of the hospital population) and did worse even with cola.
Limitations are typical of retrospective hospital data:
- Treatment was not randomised. Clinicians chose who got cola; sicker horses, horses with concurrent disease, or those already failing fluids may have been less likely to receive it.
- Dose, frequency, brand (regular vs diet), and duration were inconsistently recorded, so the paper could only analyse “cola yes/no.”
- Diagnosis and outcome assessment were not blinded.
- Concurrent treatments (fluids, prokinetics, pain relief, surgery) differed.
- Friesian breed is a strong confounder (gastroparesis and delayed emptying are common in the breed).
In addition, secondary gastric ulceration is frequent with impactions; the authors themselves noted bruxism or colic immediately after cola administration in some horses and flagged the low pH as a potential problem when ulcers are present.
Earlier equine reports were case series of persimmon bezoars, often using large volumes (sometimes >20 L/day). An in-vitro study showed cola plus enzymes can erode enterolith fragments. None of this is equivalent to a prospective randomised trial. The association with better survival is interesting and biologically plausible, but it does not prove cola is the decisive factor or that it is safe to use at home, especially without veterinary advice.
Why EGUS and impactions look the same
Equine gastric ulcer syndrome (EGUS) and gastric impaction share a long list of vague signs: picky or reduced appetite, weight loss, dull coat, mild or recurrent colic, poor performance, attitude change and sometimes bruxism or recumbency. Impactions can also cause ulcers by prolonged contact of dry material with the mucosa. Owners and even vets therefore sometimes treat “ulcer symptoms” with omeprazole for weeks while an undiagnosed mass sits in the stomach. Gastroscopy after an appropriate fast is the only reliable way to tell them apart. Several widely shared social-media cases of “Diet Coke saved my horse” began as suspected ulcers and were actually football-sized feed masses.
Do not treat with Coke; CALL A VET
Cola is not a home remedy. It is given through a nasogastric tube in a clinic so gas can escape, volume can be controlled, and the stomach can be re-scoped. Adding litres of acidic, carbonated fluid to a stomach that already cannot empty risks over-distension and rupture, especially in Friesians with gastroparesis. Regular cola’s sugar load theoretically raises laminitis risk (diet versions are preferred for that reason). Fragments of a dissolving mass can move into the small intestine and cause a new obstruction.
If the problem is actually EGUS, cola is the wrong direction. Squamous ulcers form because acid contacts the unprotected upper stomach. Omeprazole works by raising gastric pH for weeks. Coca-Cola does the opposite: it delivers more acid at a pH similar to gastric juice. There is no evidence it heals ulcers and a mechanistic reason to expect it would irritate squamous lesions. Glandular ulcers have a different pathophysiology, but flooding them with phosphoric acid is still not a treatment.
Bottom line
Get a veterinary diagnosis first. If gastroscopy shows an impaction, the vet can decide whether cola, fluids, enzymes, or surgery is appropriate and can monitor response. If it shows ulcers, licensed medication that suppresses acid production and management changes will almost certainly be the route. Guessing and taking advice from non-qualified people on social media wastes money and can make a serious problem worse.
On Animalweb we have lots of helpful resources:
- EGUS – Equine Gastric Ulcer Syndrome
- EGUS – Equine Gastric Ulcer Syndrome – The Treatment Options
- Equine Gastric Ulcer Syndrome (EGUS)
- Gastric / Stomach Supplements for horses reviewed
References
Banse, H. E., Gilliam, L. L., House, A. M., McKenzie, H. C., Johnson, P. J., Lopes, M. A. F., Carmichael, R. J., Groover, E. S., LaCarrubba, A. M., Breshears, M. A., Brosnahan, M. M., Funk, R., & Holbrook, T. C. (2011). Gastric and enteric phytobezoars caused by ingestion of persimmon in equids. Journal of the American Veterinary Medical Association, 239(8), 1110–1116. https://doi.org/10.2460/javma.239.8.1110
Gil, S. A. V., Marulanda, J. J. P., & Aranzales, J. R. M. (2021). In vitro evaluation of the dissolving effect of carbonated beverages (Coca-Cola®) and enzyme-based solutions on enteroliths obtained from horses: pilot study. Brazilian Journal of Veterinary Research and Animal Science, 58, e182579. https://doi.org/10.11606/issn
Ladas, S. D., Triantafyllou, K., Tzathas, C., Tassios, P., Rokkas, T., & Raptis, S. A. (2002). Gastric phytobezoars may be treated by nasogastric Coca-Cola lavage. European Journal of Gastroenterology & Hepatology, 14(7), 801–803. https://doi.org/10.1097/00042737-200207000-00017
Ladas, S. D., Kamberoglou, D., Karamanolis, G., Vlachogiannakos, J., & Zouboulis-Vafiadis, I. (2013). Systematic review: Coca-Cola can effectively dissolve gastric phytobezoars as a first-line treatment. Alimentary Pharmacology & Therapeutics, 37(2), 169–173. https://doi.org/10.1111/apt.12141
Livesey, L. C., Yorke, E., Parra, A., Gray, Q., Davies, C., Weldon, D., Schumacher, J., Kimura, S., Howard, C., Sierra-Rodriguez, T., & Mora-Pereira, M. (2020). Use of a carbonated beverage to disintegrate a phytobezoar obstructing the intrathoracic portion of the oesophagus of a horse. Equine Veterinary Education, 32(10), e179–e183. https://doi.org/10.1111/eve.13082
Rodriguez Hurtado, I., Stewart, A., & Pellegrini-Masini, A. (2007). Successful treatment for a gastric persimmon bezoar in a pony using nasogastric lavage with a carbonated cola soft drink. Equine Veterinary Education, 19(11), 571–574. https://doi.org/10.2746/095777307X215052
Witt, P., Hagedoorn, S., Kranenburg, L. C., & van den Boom, R. (2021). The use of cola for the treatment of gastric impactions in equids. Pferdeheilkunde – Equine Medicine, 37(6), 588–596. https://doi.org/10.21836/PEM20210604
