Once you make it to Little FungiTown, (after you face the big rock boss) you can enter the gaming arcade, which is in the eastern part of town. Go up to the top of the stairs in the arcade. Beat the high score of the game on the right, which I believe is 200. You will win an invincishroom. Mario will eat it and become sick with the bean fever. The curing plant is found in the Guffahaw ruins. After Mario is healed, you can go back to the arcade. Play the same game again and every time you get a nice score (which is easy) you will get up to 9 hee beans. Do this until you have 99 beans, go to the beanery, and make yourself some drinks!