Once Zen master Daie had a swelling on his buttocks. A doctor took a look at it and said it was critical. 

Daie asked, “Is it so serious that I might die?” 

The doctor replied, “Possibly.” 

Daie said, “Well, I am going to die anyway, so I shall practice zazen that much harder.” 

He pushed himself to sit and, eventually the swelling broke and went away. The mind of this ancient master was like this. When he got sick, he sat zazen all the more. Students of today, despite being well, don’t let up practicing zazen! 

I think that sickness changes depending upon the mind. 

When someone has hiccups, if you tell a lie with the intention of making him feel dejected, he will be shocked and try to say something, forgetting about his hiccups. On my way to China, I suffered from diarrhea on the ship, yet when a storm came up and people on the ship made a great fuss, I forgot about the sickness and it went away. 

Considering this, I think if we devote ourselves to the practice of the Way and forget everything else, no illness will arise (Shobogenzo Zuimonki, Book 5, Chapter 16).