Thirukkural

Kural - 941
The learned books count three, with wind as first; of these,
As any one prevail, or fail; 'twill cause disease.
If (food and work are either) excessive or deficient, the three things enumerated by (medical) writers, flatulence, biliousness, and phlegm, will cause (one) disease.

Kural - 942
No need of medicine to heal your body's pain,
If, what you ate before digested well, you eat again.
No medicine is necessary for him who eats after assuring (himself) that what he has (already) eaten has been digested.

Kural - 943
Who has a body gained may long the gift retain,
If, food digested well, in measure due he eat again.
If (one's food has been) digested let one eat with moderation; (for) that is the way to prolong the life of an embodied soul.

Kural - 944
Knowing the food digested well, when hunger prompteth thee,
With constant care, the viands choose that well agree.
(First) assure yourself that your food has been digested and never fail to eat, when very hungry, whatever is not disagreeable (to you).

Kural - 945
With self-denial take the well-selected meal;
So shall thy frame no sudden sickness feel.
There will be no disaster to one's life if one eats with moderation, food that is not disagreeable.

Kural - 946
On modest temperance as pleasures pure,
So pain attends the greedy epicure.
As pleasure dwells with him who eats moderately, so disease (dwells) with the glutton who eats voraciously.

Kural - 947
Who largely feeds, nor measure of the fire within maintains,
That thoughtless man shall feel unmeasured pains.
He will be afflicted with numberless diseases, who eats immoderately, ignorant (of the rules of health).

Kural - 948
Disease, its cause, what may abate the ill:
Let leech examine these, then use his skill.
Let the physician enquire into the (nature of the) disease, its cause and its method of cure and treat it faithfully according to (medical rule).

Kural - 949
The habitudes of patient and disease, the crises of the ill
These must the learned leech think over well, then use his skill.
The learned (physician) should ascertain the condition of his patient; the nature of his disease, and the season (of the year) and (then) proceed (with his treatment).

Kural - 950
For patient, leech, and remedies, and him who waits by patient's side,
The art of medicine must fourfold code of laws provide.
Medical science consists of four parts, viz., patient, physician, medicine and compounder; and each of these (again) contains four sub-divisions.