33 Serial Killers Who Used Poison

Poison isn't just for the pages of mysteries, thrillers, and crime novels. From chronic poisoning over a long period of time, to rapid poisoning that can cause instant death, many serial killers throughout history have used poison as their main weapon. This is a list of notable murderers who used poison as their modus operandi and weapon of choice.

There are many reasons why many serial killers in history have used poison to commit their murders. One of the top reasons includes collecting insurance money. Many serial killers believed that they could get away with murder since poisoning often doesn't leave much evidence. Most victims just get sick and die, making it difficult to prove the real cause of death. Many hospital workers also used poison to systematically kill their patients, giving them high doses of prescription drugs. Many serial killers used poison with the thought of nursing their victims back to health afterward in order to gain favor and public attention.

A few serial killers who used poison were found not guilty by reason of insanity and spent the rest of their lives committed to an insane asylum. Others, however, served a life sentence, multiple life sentences, or were executed, in most cases. Some of these serial killers poisoned their families, including children, and even more committed multiple murders over many years.

Read on to find out which serial killers used poison, how many murders they were responsible for, and what happened to them once they were caught.

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  • Nannie Doss
    Photo: Tulsa Police Department / Wikimedia Commons / Fair Use

    From 1927 to 1954, Doss murdered 11 people. Using rat poison, she killed her family members, including four husbands.

    She was sentenced to life in prison but did not receive the death penalty due to her gender. She died in prison of leukemia.

  • H. H. Holmes
    Video: YouTube

    Famously known as America's first serial killer, Holmes opened a hotel during the 1893 World's Fair in Chicago and lured in as many as 200 victims, including his staff, hotel guests, and his lovers. He would fill guest rooms in what became known as the "Murder Castle," with gas lines to asphyxiate his victims and was in possession of numerous bottles of various poisons. Afterward, he would make claims on their insurance policies. Holmes was hanged in 1896.

    Recently, it was discovered that H. H. Holmes was probably also responsible for some of the Jack the Ripper's murders. Confirmations of these allegations are yet to be heard.

  • Donald Harvey
    Video: YouTube

    Donald Harvey claims to have murdered more than 70 people while he worked in various hospitals. Official estimates put the number anywhere from 37 to 57 deaths. He had many different methods of murder but frequently used poisons such as cyanide and arsenic, which were administered in food by injection or IV. He often insisted that he committed the murders out of empathy for terminally ill patients.

    Harvey was apprehended in 1987 and is currently serving 20 consecutive life sentences.

  • Michael Swango

    Michael Swango
    Video: YouTube

    A former licensed physician, Swango poisoned non-patients by putting arsenic in their food and drinks. With his patients, he administered overdoses of prescribed drugs or prescribed unnecessary and dangerous drugs.

    Though he only admitted to four murders, it is estimated that he was involved in up to 60 fatal instances of poisoning. Swango is serving a life prison sentence without parole.

  • Graham Young
    Video: YouTube

    This notorious English serial killer poisoned several of his family members, including his stepmother (who he poisoned when he was only 14 years old), as well as 70 more victims. His poisonous secrets were discovered by his chemistry teacher when he found violent sketches of his family and several vials of poison. He was taken to an asylum, where he stayed for several years until doctors released him in 1971.

    It wasn't until Young found a job and several of his co-workers began dying and falling ill that he was arrested and sentenced to life in prison, where he died in 1990 in his cell. While the official cause of death was a heart attack, rumor has it that he got a taste of his own medicine.

  • Thomas Neill Cream
    Video: YouTube

    Cream was a Scottish serial killer who lived in Canada and poisoned victims in the United States, Canada, and England. He was a physician and surgeon, known for his after-hours abortion clinic and killing at least five people with chloroform and strychnine. He was convicted in 1892 and hanged for his crimes.