(medicine, anatomy) circulation (the movement of blood in the circulatory system) / circulation, distribution (the number of units of an item (copies of a newspaper, etc.) delivered to customers)

improvement, an action taken to improve / improvement, a spontaneous change for the better

(transitive) to improve, to make better / (intransitive) for something to improve on its own

betterment, improvement, amelioration

(formal) blood

A substance with mystical properties, especially one that has an effect on the body, health, or lifespan.

A medicine or drug.

(slang) A medicine or drug, especially a narcotic or other recreational drug.

medicine

blood type