Spring and Autumn tree

"There are three methods to deal with this poison," said the old man, collecting the bag of holding. "The third method is to simply alleviate the pain caused by the poison. There are three types of Spirit Fruit that you can eat which will have this effect.

"A second method can be used to suppress the effects of the poison and also reduce the frequency of the flareups. For this, you need a Spring and Autumn tree. One tree can suppress the poison for one year. By the way, this type of tree is actually capable of doing more than just suppressing a vast variety of poisons. It's very rare, but not impossible to acquire. The only down side is that using it will cause the poisoning will deepen. Also that the rebound effect is severe; if the time comes when you cannot suppress the poison any more, it will erupt violently, and you will be unable to dispel it.