Evaluation of a Chinese herbal supplement on equine squamous gastric disease and gastric fluid pH in mares

BACKGROUND: Wei Le San (WLS) is a Chinese herbal formula comprised of 9 herbs selected for their putative anti‐inflammatory effects. OBJECTIVES: To evaluate the effects of WLS administration in horses with nonglandular gastric ulcers. ANIMALS: Ten mixed breed mares (aged 7‐21 years, 401‐567 kg body weight). METHODS: Experimental design was a blinded, prospective, 2‐period crossover study. All horses received a placebo (25 mL dextrose‐based syrup; n = 10) and the treatment (WLS, 5 g in 25 mL dextrose‐based syrup; n = 10), administered twice daily. Horses underwent a 1‐week, alternating feed‐deprivation period to induce or worsen existing ulcers; treatment began on day 7. Gastroscopic examination was performed on d0, d6, and d35, with gastric fluid pH obtained on d6 and d35. Gastric ulcer scores assigned by 3 masked observers were averaged for each examination. RESULTS: Ulcer number scores for horses treated with WLS (median = 0; range, 0‐4) was not different from the untreated controls (median = 0.5; range, 0‐4; P = .81) by the end of the treatment period. Ulcer severity score for treated horses (median = 0; range, 0‐1) was also unchanged compared to the control group (median = 0.5; range, 0‐1; P = .85). Gastric pH was not altered by either treatment, with a median of 2.1 (range, 1.9‐4.1) for the horses treated with WLS and 2.8 (range, 1.6‐7.2) in the untreated controls (P = .46). CONCLUSIONS AND CLINICAL IMPORTANCE: The experimental model used to induce gastric ulceration was unable to discern a difference between the herbal supplement and the placebo in normal horses.