To evaluate the efficacy of a combination of a unique pectin-lecithin complex (Apolectol®), live yeast and magnesium hydroxide in the prevention of equine gastric ulcer syndrome (EGUS) and faecal acidosis in Thoroughbred racehorses.


Thoroughbred racehorses in training with grade ≤ II/IV EGUS were identified on gastroscopy. Horses were randomised to receive either 95 g Apolectol®, 2 g live yeast (Saccharomyces cerevisiae – CNCM I-1077) and 20 g magnesium hydroxide or 95 g of a commercial feed pellet as a placebo 1–4 h prior to exercise. Faecal analysis was performed weekly and faecal acidosis defined as a faecal pH of <6.2. Gastroscopy was repeated at 24–27 days.


Mean ulcer scores did not increase in the treatment group for either the squamous (0.8 ± 1.0 to 0.5 ± 0.8; P = 0.133) or glandular (0.7 ± 0.8 to 0.7 ± 1.1; P = 0.38) mucosa. In contrast, in the placebo group mean ulcer scores significantly increased over time for the squamous (1.1 ± 0.7 to 2.2 ± 1.2; P = 0.013), and increased, but not statistically so, for the glandular (0.6 ± 0.7 to 1.6 ± 1.5; P = 0.065) mucosa. Over time horses in the placebo group were more likely to experience worsening of their ulcer score in both the squamous (P = 0.03) and glandular (P = 0.03) mucosa than horses in the treatment group. Horses in the placebo group were more likely to have faecal acidosis over time (P = 0.03).


The combination of Apolectol®, live yeast and magnesium hydroxide is an effective prophylactic against EGUS and reduces the risk of faecal acidosis in horses in high-intensity work.

Practical significance

The combination studied provides a viable, nonpharmaceutical means for the prevention of EGUS and faecal acidosis in high-risk horses.

Acknowledgements provided a videoendoscope free of charge for the purposes of this study.

Ethical animal research

The study was performed in accordance with the New South Wales Department of Primary Industries guidelines for clinical studies and the New South Wales Animal Research Act of 1985. Informed consent from the owner or the trainer was obtained at the time of enrolment to the study. Sources of funding: This study was funded by Boehringer Ingelheim. Conflicts of interest: B.W. Sykes is employed as a consultant by Boehringer Ingelheim.