Asparagus has poisons within it that are easily eliminated by the kidneys, which exist the body through the urinary tract. Eat too much asparagus and it can actually dehydrate you as your body uses its water reserves to help pull out the toxins. That said, the toxins are so mild they pose no threat and asparagus is so full of vitamins that it is definitely a good health food. Eating it will actually help your kidneys to perform more efficiently in spite of a small increase in work as you digest the plant.