Cyanide Toxicity: How It Works

Cyanide Toxicity: How It Works

This article relates to Death in the Jungle

Death in the Jungle tells the true story of Jim Jones, the preacher-turned-cult-leader who founded the infamous Jonestown settlement, a socialist community that became a site of mass murder. Jones was interested in "revolutionary suicide" and asked Jonestown doctor Larry Schacht to find a method for it; Schacht began researching the use of the fast-acting poison cyanide, eventually concluding that death by cyanide was painful but quick—an accurate but understated assessment.

Cyanide is a naturally occurring substance produced by a variety of bacteria, fungi, and algae as well as some by plants, including apples and peaches. It has been understood as a lethal chemical, poison, and potential weapon since at least the Roman Empire; in 1782, it was first synthesized in a lab, and since then has been used for chemical warfare, including in both WWI and WWII. It also has less sinister uses, including as a pesticide.

Cyanide exposure at low doses is common, and the body can readily convert the compound into something harmless. For example, measurable levels are found in cigarette smoke, car exhaust, and smoke from structural fires. But exposure in large doses, whether by inhalation, ingestion, or topical exposure, overwhelms the conversion process and leads to toxicity. Inhalation of hydrogen cyanide, even at a dose as seemingly low as 50 parts per million, can lead to death within seconds or minutes; ingestion (the method used at Jonestown) of about twice that can be lethal in minutes to hours.

The way cyanide toxicity works is that the compound prevents cells from using the oxygen in the bloodstream, quickly asphyxiating the cells. As cells die en masse, tissues begin to shut down, followed by organ failure and, without treatment, death. Tissues that use lots of oxygen—specifically, the brain and the heart—are affected first and worst, leading to a wide range of central nervous system and cardiovascular symptoms, like an abnormal heart rate, hypotension, headache, lethargy, and vomiting, followed by seizures, pulmonary edema, coma, and death.

Cyanide exposure via chemical attacks or suicide is usually lethal, but occupational or accidental exposures via smoke inhalation are more common and may be treated. The National Poison Data System reported 853 cyanide exposures in the US between 2019 and 2023 with a fatality rate of only 1.6%. However, those who survive a sub-lethal exposure need to be observed long-term as they may be at risk of developing negative neurological symptoms.

At Jonestown, Schacht and Jones used a mixture of cyanide, Valium, and Flavor-Aid (a drink mix similar to Kool-Aid) to kill over 900 members of the settlement. Schacht's assessment of cyanide poisoning was generally accurate, but his clinical observations failed to consider the horror of watching friends and family gasp for breath, convulse, and finally die. As parents watched their children die, one of Jones' mistresses lied, assuring them that the children "are not crying from pain…it's just a little bitter tasting." Understanding this process of death by cyanide gives a new horror to the ending of Death in the Jungle.

Image courtesy of the National Museum of Health and Medicine, CC BY 2.0

Filed under Medicine, Science and Tech

This article relates to Death in the Jungle. It first ran in the May 21, 2025 issue of BookBrowse Recommends.