Thorn apple or jimsonweed has a foul odor and taste, which makes it less desirable to horses if hay or grass is available. Horses experience weak pulses, dry mouths, convulsions, diarrhea, and even comas.
Many of these toxic plants can be very dangerous to your horse. There are also many more plants and trees that can cause adverse reactions if consumed. Practice excellent field management to ensure your horse doesn’t eat something he shouldn’t.