There are two general categories of illness that afflict human beings. The first is the sickness of the body. The four great elements of the body: the earth, water, fire, and wind each has 101 kinds of sickness reaching 404 altogether. These physical illnesses can be cured by medicine prepared by great doctors such as Ch’ih Shui, Liu Shui, Jīvaka, and Pien Ch’üeh. The second kind of sickness is mental sickness, namely the 84,000 evil passions arising from the three poisons of greed, anger, and ignorance. These sicknesses of mind can only be cured by the Buddha. Even the divine powers of the two heavenly beings and three hermits of Brahmanism in India cannot cure it, and certainly not the powers of Shen Nung and Yellow Emperor of Confucianism.
Nakatsukasa Saemonnojō-dono Gohenji, A Reply to Lord Nakatsukasa Saemonnojō, Writings of Nichiren Shōnin, Volume 6, Followers I, Page 145-146