A recent study found that a combination of psyllium and magnesium sulphate was effective at clearing accumulations of sand in the large colon.

Psyllium, a sort of “super-bran”, is used in horses for treatment and prevention of sand colic. When mixed with water, it swells to up to 10 times its original volume, turning into a jelly-like substance which is thought to ease the passage of sand through the digestive tract. It may also have a direct influence on gut motility by acting on chemical receptors. Magnesium sulphate (MgSO4 – also known as “Epsom salts”) acts as an osmotic cathartic that draws water in the gut contents and enhances intestinal motility.

Kati Niinistö and colleagues at the Faculty of Veterinary Medicine, University of Helsinki, Finland evaluated a combination of psyllium and MgSO4 for the removal of large colon sand accumulations in horses without clinical signs of acute colic.

Forty horses were enrolled in the study. They had radiological evidence of sand accumulation in the large colon. None of the horses showed signs of colic.

The horses were divided at random into two groups. Twenty were treated with psyllium (1g/kg bodyweight) and MgSO4 (1g/kg bodyweight) administered by nasogastric intubation once daily for 4 days. Twenty control horses received no treatment.

Horses were given free access to timothy hay and water during the study. Neither group had access to soil.

The amount of accumulated sand in the large colon of each horse was evaluated radiographically before and after four days of treatment.

The research team found that medical treatment was more effective than just restricting access to sand. Colonic sand accumulation resolved with 4 days of treatment with psyllium and MgSO4 in 75% of treated horses in the study. In contrast, the sand cleared spontaneously in only 20% of the untreated control group.