Problemata Aristotelis

And if they are given more than is just, they will kill. But those that kill even if they are given in small amounts, these we say are not medicaments but toxins. We do not even call those things medicaments that cannot purge by the quality of their own kind. For there are many things in the genus of food that, if taken in large quantities, will be able to do this, such as milk, oil, and must. But all these, because they are less easily digested, therefore purge—and not all of them, but some. For to some, things are easy or difficult to digest. Therefore, the same medicaments are not for everyone, but are found to be proper to many. Finally, a medicament must be not only immune to digestion but also capable of causing movement, just as the method of exercising, whether accessing from the outside or the inside, excretes matter only through alien motion.

Why can odorous kinds of both seeds and plants move urine? Is it because they are warm and easy to digest? In this genus, we place those that incite urine. For this innate power of heating is quickly thinned. An odor also carries no corpulence. For even those things that give off an odor most fully, such as others, move urine by their heat, or rather possess the power of dissolving. It is certain that odorous seeds are warm.

Why must one use dry, sharp, and bitter medicaments for impure and foul ulcers, while for pure and healing ones, they apply only moist things? Is it because from the impure, something must be drawn out, which should be removed only by a moist and foreign humor? But the kind of medicament that is biting, sharp, and bitter can do this and is more dry than moist. But those that are pure desire only a scar.

Why does immoderate libido plague diseases that are contracted from phlegm? Is it because the genital seed is a drawing out of a certain excrement, and therefore nature prefers it to phlegm?