Primum non nocere

Primum non nocere.
Po pierwsze nie szkodzić.
First Do No Harm

http://en.wikipedia.org/wiki/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.

Nonmaleficence, which derives from the maxim, is one of the principal precepts of medical ethics that all medical students are taught in medical school and is a fundamental principle for emergency medical services around the world. Another way to state it is that "given an existing problem, it may be better to do nothing than to do something that risks causing more harm than good." It reminds the physician and other health care providers 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. Since at least 1860, the phrase has been for physicians a hallowed expression of hope, intention, humility, and recognition that human acts with good intentions may have unwanted consequences. A closely related phrase is "Sometimes the cure is worse than the ill."