Unripened persimmons contain the soluble tannin shibuol, which, upon contact with a weak acid, polymerizes in the stomach and forms a gluey coagulum, a "foodball" or phytobezoar, that can affix with other stomach matter [REF].
Horses may develop a taste for the fruit growing on a tree in their pasture and overindulge also, making them quite ill [REF].