Treatment for disease or ill-health is not without its risks. These risks may be inherent to the treatment, such as known side effects of medication, or due to the actions or omissions of healthcare professionals, such as accidentally cutting an adjacent organ during surgery or failing to give the patient prophylactic antibiotics to prevent post-operative infection. Terms used to describe treatment complications and injury to patients include the following: iatrogenic injury or iatrogenic disease; medical accidents; medical mishaps; adverse events; negligence; adverse events; medical mistakes; medical error and critical incidents. Some of these terms have specific definitions while others are general terms that are often used interchangeably. The definition, use and development of these terms are described below. This is followed by an outline of methods used to help our understanding of medical harm, the impact on patients, families and staff, and concludes with a section on how harm to patients can be prevented.

Iatrogenic disease and patient harm

The term ‘iatrogenic’ comes from the Greek word for physician ‘iatros’ and from ‘genesis’, meaning origin; iatrogenic disease therefore is illness which is induced, in some way, by a physician. With the advances of medical science in the mid-twentieth century, particularly the development of penicillin and other antibiotics, the term iatrogenic disease broadened in scope. By the mid-1950s some doctors were beginning to realize that there were potential hazards associated with the enormous increase in drug use and availability (Sharpe & Faden, 1998).