Poison is emerging as the most dangerous threat to wild tigers in Thailand.
Poachers want to kill these animals because their skins, bones and teeth can be sold for large amounts of money.
More and more poachers are putting poisonous chemicals into meat and leaving it out as bait.
If eaten, it will kill the tiger.
It's thought there are only around 200 tigers left in Thailand.
In one of the country's most important tiger sanctuaries, 200 guards try to protect the animals.
But they have to patrol an area three times the size of London so it's tough, and eager poachers keep finding new ways to kill the tigers.