Thus I have heard: One time, the Buddha was staying at the Residence of Sages in the Deer Preserve of Bārāṇasī.
It was then that the Bhagavān addressed the monks, “When someone accomplishes four things, they are called the great king of doctors who possesses what a king should, with a king’s lot. What are the four? The first is skill in knowing illnesses. Second is skill in knowing the source of an illness. Third is skill in knowing the treatment for an illness. Fourth is skill in knowing that an illness won’t occur again in the future once it has been treated.
“What’s called a good doctor’s skill in knowing illnesses? It means a good doctor is skilled in knowing: ‘Such and such are the various illnesses.’ This is called a good doctor’s skill in knowing illnesses.
“What’s called a good doctor’s skill in knowing the source of an illness? It means a good doctor is skilled in knowing: ‘This illness arises because of wind … arises because of phlegm … arises because of saliva … arises because various colds … arises because present circumstances … arises because of the season.’ This is called a good doctor’s skill in knowing the source of an illness.
“What’s called good doctor’s skill in knowing the treatment for an illness? It means a good doctor is skilled in knowing: ‘Various illnesses should be treated with ointments, with emetics, with laxatives, with nasal irrigations, with suffusions, or with sweating.’ This is called a good doctor’s skill in knowing the treatment for an illness.
What’s called a good doctor’s skill in knowing that an illness won’t occur again in the future once it has been treated? It means a good doctor is skilled in treating various illnesses, bringing them to a final end to that they do not occur again in the future. This is called a good doctor’s skill in knowing that an illness won’t occur again in the future once it has been treated.
“The Tathāgata, the Arhat, the Completely Awakened One is the great king of doctors. He achieved these four virtues to heal the illness of sentient beings in the same way. What are the four? The Tathāgata knows ‘this is the noble truth of suffering,’ and he truly knows it … ‘this is the noble truth of suffering’s formation,’ and he truly knows it … ‘this is the noble truth of suffering’s cessation,’ and he truly knows it … ‘this is the noble truth of the path to suffering’s cessation,’ and he truly knows it.
“Monks, that worldly good doctor doesn’t truly know the treatment for the root of birth … doesn’t truly know the treatment for the root of old age, illness, death, sorrow, lamentation, trouble, and pain. The Tathāgata, Arhat, and Completely Awakened One is the great king of doctors who truly knows the treatment for the root of birth … truly knows the treatment for the root of old age, illness, death, sorrow, lamentation, trouble, and pain. Therefore, the Tathāgata, Arhat, and Completely Awakened One is called the great king of doctors.”
After the Buddha spoke this sūtra, the monks who heard what the Buddha taught rejoiced and approved.