Munchausen syndrome by proxy (MSBP) is a mental disorder and form of child abuse in which a caregiver—usually a mother—claims or causes an illness in another person, usually her child. The caregiver may directly hurt the child to produce symptoms or may cause the child to undergo unnecessary medical tests or treatments that are often painful and potentially harmful.

A caregiver may:

• Falsely claim a child has experienced serious symptoms, such as seizures, diarrhea, vomiting, or apnea.
• Contaminate test results to make a child appear ill.
• Physically harm the child to produce symptoms.

Munchausen syndrome by proxy (also called factitious disorder by proxy) sometimes is triggered by a child having a true illness from which the caregiver gains attention and satisfaction. A caregiver sometimes victimizes more than one child but not at the same time. A child who is a victim of Munchausen syndrome by proxy is at increased risk for developing mental health problems and complications of unnecessary medical treatment.

Diagnosis requires careful scrutiny and documentation by a team of health professionals who will involve police, children's protective services, and the courts. The caregiver is held legally accountable for his or her actions and requires mental health counseling.