Method · a Light

Ibn Sina set the conditions for judging a drug

In the second book of the Canon, Ibn Sina asks how anybody can know that a drug works, and lays down conditions. The drug must be pure and unspoiled, so that nothing else is being tested. It must be tried on a single disease and not on a mixture of complaints. Its strength must be matched against the strength of the illness. The time it takes to act must be noted. The effect must appear again and again in many cases, because a result seen once may be chance. And the trial must be made on human beings, since what a drug does to a horse proves nothing about a man. This is not a controlled trial, and there is no comparison group anywhere in it. It is a set of rules for not being fooled.

Ibn Sina · Canon, Book Two, c. 1025