In medical ethics, a doctor's obligation to provide competent and appropriate care to his or her patients is guided by the phrase "First, do no harm.” All healthcare professionals are required to provide a certain standard of care or “duty of care” for their patients. When a healthcare provider fails to conduct his or her job in a rational, ethical manner or offers treatment that causes bodily injury or mental harm to a patient, they have breached that standard of care. This breach of duty, also known as medical negligence, may lead to a medical malpractice lawsuit against the responsible physician.