The dose makes the poison

—Paracelsus'The dose makes the poison' (Latin: sola dosis facit venenum) is an adage intended to indicate a basic principle of toxicology. It is credited to Paracelsus who expressed the classic toxicology maxim 'All things are poison, and nothing is without poison, the dosage alone makes it so a thing is not a poison.' This is often condensed to: 'The dose makes the poison' or in Latin, 'Sola dosis facit venenum'. It means that a substance can produce the harmful effect associated with its toxic properties only if it reaches a susceptible biological system within the body in a high enough concentration (i.e., dose).