Aloe Vera vs. Omeprazole for Equine Gastric Ulcer Treatment
Check the supplement stash at any performance stable, and you are likely to find a bottle of aloe vera juice, which some horse owners reach for to prevent or treat ulcers. But is it effective? To shed some light on this practice, a team of researchers at the University of Adelaide, in Australia, conducted a randomized, blinded clinical trial comparing the efficacy of aloe vera to omeprazole for treating equine gastric ulcer syndrome, the first study of its kind.

The team studied 40 horses with Grade 2 or higher ulcer lesions (confirmed via gastroscopy) in the upper portion (squamous) and/or lower portion (glandular) of the stomach, randomly assigning them to one of two groups. One group received 17.6 mg/kg body weight (a dose they settled on using data from similar studies performed in rats) of dehydrated inner leaf aloe vera powder (produced by Aloe Vera Australia), which was reconstituted with water into a paste, twice daily, while the other group received 4 mg/kg body weight omeprazole once daily. After four weeks of treatment, the team performed a repeat gastroscopy. Horses with persistent ulceration received a course of omeprazole and were re-examined after four weeks.

The team found that while horses treated with aloe vera did show squamous lesion improvement, those on the omeprazole regimen showed greater improvements overall. Fifty-six percent of horses on aloe vera improved by at least one lesion grade, compared to 85% of those receiving omeprazole. Healing rates (ulcers becoming Grade 1 lesions or less) were 17% for the aloe vera group and 75% for the omeprazole group. The healing rate for horses receiving a second omeprazole treatment was only 37%, however. The number of horses with glandular ulcers, far fewer than those with squamous ulcers, was too small for statistical analysis, the team said.

Samantha Franklin, BVSc, PhD, Dipl. ACVSMR, MRCVS, an associate professor of equine physiology at the university, said the team found that “ulcer healing in horses treated with omeprazole was less likely to occur in horses with prolonged gastric emptying. The cause of this is uncertain. However, it is possible that feed retained within the stomach may inhibit omeprazole absorption or may mechanically influence healing and/or cause new lesion formation.”

Franklin added that studies using higher doses of aloe vera would be useful. “We could not rule out the possibility that a higher dose would have resulted in higher rates of improvement, although the study dose was higher than that commonly given to horses and above that recommended by the manufacturer,” she said.

“Whilst we found that aloe vera was not as effective as omeprazole, some horses did show some improvement in ulcers scores in the upper part of the stomach,” she continued. “The factors contributing to glandular lesion development and treatment are still poorly understood and require further investigation. A larger study to examine the effectiveness of aloe vera on glandular ulcers would be of interest.”

Additionally, she said, horses with a history of gastric ulcers frequently relapse once treatment stops. “It would be interesting to investigate whether aloe vera might be used as a preventative treatment to reduce ulcer recurrence,” she said.

The Bottom Line

“Owners that suspect their horses might be suffering from stomach ulcers should contact their veterinarian to obtain a diagnosis, which can be made by performing a gastroscopic examination,” Franklin said. “If ulcers are found, omeprazole remains the current treatment of choice.”

This study, “Comparison of aloe vera and omeprazole for treatment of equine gastric ulcer syndrome,” was published in Equine Veterinary Journal.