Medical malpractice is an act or omission by a health care provider which deviates from accepted standards of practice in the medical community and which causes injury to the patient. Simply put, medical malpractice is professional negligence that causes an injury.

At the outset it is important to remember that virtually every country in the world operates its own unique legal system, and within some countries, there is more than one system operating within the same national borders.

The plaintiff is or was the patient, or a legally designated party acting on behalf of the patient, or -- in the case of a wrongful-death suit -- the executor or administrator of a deceased patient's estate.

The defendant is the health care provider. Although a 'health care provider' usually refers to a physician, the term includes any medical care provider, including dentists, nurses, and therapists. As illustrated in Columbia Medical Center of Las Colinas v Bush (122 S.W. 3d 835, Texas, 2003), "following orders" may not protect nurses and other non-physicians from liability when committing negligent acts. Relying on vicarious liability or direct corporate negligence, claims may also be brought against hospitals, clinics, managed care organizations or medical corporations for the mistakes of their employees.