The gastric ulcers are recurrent in racing horses with a prevalence of between 50% and 90%. To treat this pathology, chemical drugs (based on omeprazole) are administrated during a long period. However, horse racing company regulations prohibit them as part of the fight against doping.

The use of a non-doping food supplement presents a real interest in horses’ gastric mucosa protection. In 2023, a clinical study was carried out on 20 active horses to demonstrate the Velay Green Clay benefits (silicates and/or aluminosilicates) for the protection and the healing of stomach walls.

Good to know: the Velay Green Clay is already authorized as an additive for animal feed in the European Union, and already used for its antidiarrheal properties.

Aims of the study on the Velay Green Clay effectiveness in case of equine gastric ulcers treatment

  1. Evaluation of the Velay Green Clay as a supplement in affected horses.
  2. Validation of the optimal concentration and evaluation of the palatability for an oral administration.
  3. Evaluation of the Velay Green Clay benefits as a complement to medicinal treatment.
  4. Estimation of changes in physical condition and behavior in horses after the administration.


  • Selection of horses following clinical examination when gastric ulcer is suspected.
  • Gastroscopies under anesthesia after a diet at least 12 hours.


  • The administration of the Velay Green Clay paste at 50% of clay  (product A) in a single 60 ml oral syringe per day.
  • Administration of Omeprazole (product B) 4 Mg/kg per day.
  • Administration of treatment A or B every morning before each meal in one order or the other (cross-over study).
  • Protocol over 28 days.


Based on the results of testing performed, the Velay Green Clay can be considered as an interesting supplement in horses suffering from the EGUS syndrome. The Velay Green Clay can be used alone as first intention with an improvement in scores of 44% in this study.

In addition to Omeprazole, the Velay Green Clay allows an improvement in scores of 67 to 79% at 28 days. Results obtained on the regions of small curvature and the pylorus, generally ulcerative and painful areas, are particularly interesting.

The Velay Green Clay is limiting the recurrence of ulcers when omeprazole treatment is interrupted. It is the perfect complement for competitions or races requiring regulatory compliance with an anti-doping deadline. Whatever protocol used, horses are better recovering. They are more friendly in the box, more manageable under the saddle and in care. They have better appetites, including those with a selective one. We observe a weight gain of 20 to 80 kg as well as an improvement of hair quality. The presentation and palatability of the dough were praised.