Primum non nocere

Primum non nocere is a Latin phrase that means "first, do no harm." The phrase is sometimes recorded as primum nil nocere.

Non-maleficence, which is derived from the maxim, is one of the principal precepts of bioethics that all healthcare students are taught in school and is a fundamental principle throughout the world. Another way to state it is that, "given an existing problem, it may be better not to do something, or even to do nothing, than to risk causing more harm than good." It reminds the health care provider that they must consider the possible harm that any intervention might do. It is invoked when debating the use of an intervention that carries an obvious risk of harm but a less certain chance of benefit.