Suicide pill A suicide pill ( also known as a 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 . This is normally done 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 leak sensitive information . As a result , lethal pills have important psychological value to persons carrying out missions with a high risk of capture and interrogation . Their main advantage is that they can be concealed and evade detection more easily than other methods of suicide . The concept of the suicide or poison pill does not limit itself to pills and actual death , but rather may lend itself in a colloquial manner to anything that has fatal or highly unpleasant consequences to something if deliberately done . Such a " poison pill " attempts to prevent a certain action or choice by killing the attractiveness of that choice , typically by damaging or ruining that option or thing should that choice ever be made . For example , a contract or company might contain a " poison pill " clause or provision that makes a certain scenario , such as a hostile takeover , unattractive or impossible . Description . Traditionally , lethal pills are oval capsules , 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 is important to note that purpose - made lethal pills ( of the rubber - coated type ) are never swallowed whole . Instead , they are first crushed between the user ' s molars to release the fast - acting poison contained within . Brain death occurs within minutes and the heartbeat stops shortly after . The Central Intelligence Agency began experimenting with saxitoxin , an extremely potent neurotoxin , during the 1950s . 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 . Another method of suicide offered to U - 2 pilots was a small glass ampule called the " L - pill " containing liquid potassium cyanide . Putting the pill in the mouth and biting down would cause death in 10 to 15 seconds , but most pilots chose to not take the " L - pill " with them . Metaphorical uses . 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 . Variations of the suicide pill include the Jonestown Defense , the Scorched Earth defense , and the Golden Parachute . NASA controversy . A widely held belief 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 .