Leeches should be kept a day before applying them. They should be squeezed to make them eject the contents of their stomachs.
There are no incurable diseases – only the lack of will. There are no worthless herbs – only the lack of knowledge.
Width of life is more important than length of life.
An ignorant doctor is the aide-de-camp of death.
The knowledge of anything, since all things have causes, is not acquired or complete unless it is known by its causes.
The more brilliant the lightning, the quicker it disappears.
When you do not know the nature of the malady, leave it to nature; do not strive to hasten matters. For either nature will bring about the cure or it will itself reveal clearly what the malady really is.
Is it the fault of wine if a fool drinks it and goes stumbling into darkness?
That whose existence is necessary must necessarily be one essence.
The different sorts of madness are innumerable.
As to the mental essence, we find it in infants devoid of every mental form.
Medicine considers the human body as to the means by which it is cured and by which it is driven away from health.
Those who deny the first principle should be flogged or burned until they admit that it is not the same thing to be burned and not burned, or whipped and not whipped.
A horse is simply a horse.
Now it is established in the sciences that no knowledge is acquired save through the study of its causes and beginnings, if it has had causes and beginnings; nor completed except by knowledge of its accidents and accompanying essentials.
The physical signs of measles are nearly the same as those of smallpox, but nausea and inflammation is more severe, though the pains in the back are less.
When a thing standeth long in salt, it is salt, and if any thing stand in a stinking place, it is made stinking; and if any thing standeth with a bold man, it is made bold, and if it stand with a fearefull man, it is made fearefull.
Science and art leave societies in which they are not respected Avicenna.