When I was younger, I watched this old style animated movie,I remember very vague details about it. It looked as though it might be japanese, but I could be wrong. I distinctly remember a little boy, wearing a purple shirt, black hair. Possibly green pants. He's in a forest, I recall a waterfall. I also recall him eating things in the forest that look like white radishes. (not mushrooms). He is also bitten in the leg by a snake or some creature and is poisoned by it. I think someone/something sucks the poison out of his leg or he eats those white radish things and feels better, not sure. But I distinctly remember him getting bitten. I also remember him coming to a japanese/chinese town and seeing a girl that he wants to save. I remember him consulting a medicine man there. I think he's imprisoned and the girl drops packages into his cell with food.
I remember really loving this, please help me find out what it's called? :)