A suicide pill (also known as the cyanide pill, kill-pill, lethal pill, Death-pill, or L-pill) is a pill, capsule, ampoule or tablet containing a fatally poisonous substance that a person ingests deliberately in order to quickly commit suicide. Military and espionage organizations have provided their agents in danger of being captured by the enemy with suicide pills and devices which can be used in order to avoid an imminent and far more unpleasant death (such as through torture), or to ensure that he/she cannot be interrogated and forced to disclose secret information. As a result, lethal pills have important psychological value to persons carrying out missions with a high risk of capture and interrogation. The option to kill oneself in such extreme circumstances is generally recognized by society as a form of rational suicide.
The term "poison pill" is also used colloquially for a policy or legal action set up by an institution that has fatal or highly unpleasant consequences for that institution if a certain event occurs. Examples are the poison pill shareholders rights amendments inserted in corporate charters as a takeover defence, and wrecking amendments added to legislative bills.
During World War II, British and American secret services developed the "L-pill" (lethal pill) which was given to agents going behind enemy lines. It was an oval capsule, approximately the size of a pea, consisting of a thin-walled glass ampoule covered in brown rubber (to protect against accidental breakage) and filled with a concentrated solution of potassium cyanide. It could be carried in the mouth, shaped as a false tooth; if it was accidentally swallowed it would pass harmlessly through the body. To use, the agent would bite down on the pill, crushing the ampoule to release the fast-acting poison. Brain death occurs within minutes and the heartbeat stops shortly after.
After the war, the L-pill was offered to pilots of the U-2 reconnaissance plane, who were in danger of being shot down and captured flying over Eastern Europe, but most pilots declined to take it with them. The Central Intelligence Agency began experimenting with saxitoxin, an extremely potent neurotoxin, during the 1950s as a replacement for the L-pill. According to CIA Director William Colby, a tiny saxitoxin-impregnated needle hidden inside a fake silver dollar was issued to Francis Gary Powers, an American U-2 pilot who was shot down while flying over the USSR in May 1960.
- Field Marshal Erwin Rommel was forced to commit suicide with a cyanide pill following his implication in the July 20 plot against Hitler. Additionally, Eva Braun, and a number of leading Nazis, such as Heinrich Himmler and Hermann Göring, are known to have committed suicide using lethal pills containing a solution of cyanide salts.
- In 1985, serial killer Leonard Lake committed suicide using cyanide pills sewn into his clothes after he was arrested for possessing a suppressor and an unregistered handgun, knowing that further investigation into his life would uncover his more serious crimes.
- In 1987, two North Korean agents bit into ampules hidden in the filter tips of cigarettes after they were detained in Bahrain as suspects in an airplane bombing. One agent died.
- During the Sri Lankan Civil War between 1987 and 2009, the separatist suicide bombers of the Tamil Tigers wore a potassium cyanide necklace. If they were captured by the Sri Lanka Army, they would bite into the tablet at the end of the necklace. In addition to suicide bombers, since 1976 almost all separatists of this organization wore suicide pills. This is the most modern day wide scale use of potassium cyanide as a suicide tool. The women were the most publicized, carrying a tablet adhered to their tooth.
- One of the objectives of the Dieppe Raid was to discover the importance and performance capability of a German radar station on the cliff-top to the east of the town of Pourville. To achieve this, RAF Flight Sergeant Jack Nissenthall, a radar specialist, was attached to the South Saskatchewan Regiment. He was to attempt to enter the radar station and learn its secrets, accompanied by a small unit of 11 men of the Saskatchewans as bodyguards. Nissenthall volunteered for the mission fully aware that, due to the highly sensitive nature of his knowledge of Allied radar technology, his Saskatchewan bodyguard unit were under orders to kill him if necessary to prevent him being captured. He also carried a cyanide pill as a last resort.
In economics, a suicide pill is a form of risk arbitrage used by corporations to thwart hostile takeover attempts. As an extreme version of the poison pill defense, this crippling provision refers to any technique used by a target firm in which takeover protection could result in self-destruction.
A widely held myth asserts that astronauts carry suicide pills in case they are unable to return to Earth. This was disputed by astronaut Jim Lovell, who co-wrote Lost Moon (later renamed Apollo 13). Considering the fact that marooned astronauts could easily commit suicide by simply venting the air from their spacecraft or suits, such a pill would not likely be necessary.
- Robert Hall (5 June 2009). "Allied 'bandits' behind enemy lines". BBC News. Normandy.
- Pedlow, Gregory W.; Welzenbach, Donald E. (1992). The Central Intelligence Agency and Overhead Reconnaissance: The U-2 and OXCART Programs, 1954-1974 (PDF). Washington DC: History Staff, Central Intelligence Agency. pp. 65–66.
- Unauthorized Storage of Toxic Agents. Church Committee Reports. 1. The Assassination Archives and Research Center (AARC). 1975–1976. p. 7.
- Don Oberdorfer (5 December 2001). The two Koreas: a contemporary history. Basic Books. p. 184. ISBN 978-0-465-05162-5. Retrieved 6 December 2011.
- John Emsley. Molecules of murder: criminal molecules and classic cases. ISBN 978-0-85404-965-3.
- Atkin 1980, p. 136.
- Robert Zemeckis, Steve Starkey, Contact DVD audio commentary, 1997, Warner Home Video