Convicted of 15 murders and responsible for the deaths of 218 patients identified by inquiry but is believed to have killed up to 250 people.[49] He injected diamorphine into his patients and then falsified the medical records, reporting that his patient had been in poor health. Known (after his arrest only) as Doctor Death.[50] Hanged himself in prison.

Ran hospitals in Shanxi, Shaanxi, and Henan despite lacking a license or any kind of medical formation, where he administered "miracle cures" that contained high amounts of poisonous sodium sulphate.

Killed more than 103 newborn children. As a maternity nurse she killed infants born to parents unwilling to care for them during the prohibition of abortion in Japan. Arrested in 1948 and sentenced to 4 years in prison.

Massof, who worked at Kermit Gosnell's abortion clinic, testified that he snipped the spines of more than 100 babies after seeing them show signs of life

Medical doctor found to have killed 43 wounded policemen, soldiers and officials in Kirkuk; was a member of an insurgent cell.

Self-professed Angel of Death. Worked as an orderly in Cincinnati-area hospitals and preyed on his patients. Claims to have killed 87 patients starting at age 18. Active 1970–1987. Serving 28 life sentences in Ohio.

Nurse that confessed to poisoning 31 patients for her own sexual gratification. After overdosing them she would get in bed and lie with them as they died. Found not guilty by reason of insanity and interned in a mental institution until her death in 1938.

Male nurse who killed 29 patients; Sentenced to life on November 20, 2006.

A Nurse Aide who poisoned victims with gevisol and ivisol. His actions were called "The Hospital Murders" (Swedish: Sjukhusmorden)

Active 1926 and from 1942 to 1944. Petiot is suspected of having killed up to 63 in total. Executed in 1946.

Norwegian nurse and most prolific known serial killer in Scandinavian history, convicted on 18 March 1983 of poisoning at least 22 patients with Curacit; however he initially confessed to 27 murders; after he retracted his confessions and he told he had killed 138 patients. Was released from prison in 2004 after serving 21 years, the maximum punishment possible by Norwegian law.

Nurse in New Jersey and Pennsylvania who murdered at least 29 patients between 1988 and 2003, but experts believe the number could be as high as 400. Cullen has admitted to more murders, which authorities believe are likely, but the murders cannot be verified due to lack of records

Doctor who killed his patients in St. Petersburg. Suspected of 19 murders

Nursing home worker who fatally poisoned at least 11 elderly residents in Olot. During trial he claimed them to be mercy kills intended to spare the victims of further suffering, even though three of them were administered caustic cleaning materials that caused severe burns and a long agony

Poisonings of ten patients at the Veteran's Administration Hospital in 1975. Filipino nurses Filipina Narciso and Leonora Perez were tried for the crimes.

Born Carl Menarik, Austrian who killed 8 elderly patients by poisoning in New York. Sent to an asylum and escaped. Never caught.