The American persimmon can be poisonous to horses. The problem is associated with tannins in the fruit. The tannins can precipitate from the fruit in the stomach and form a sticky mass. This mass can cause ulcers in the stomach and even lead to rupture of the stomach if the horse was to eat a large quantity of the fruit. This can also cause colic due to impaction in the stomach or the small intestine. Signs are colic and weight …