Senicide, or geronticide, is the killing of the elderly, or their abandonment to death.
Pythagorean doctrine held that all creatures were being punished by the gods who imprisoned the creatures' souls in a body. Thus, any attempt to alter this punishment would be seen as a direct violation of the gods' wills. In the fourth century BC, the Hippocratic Oath was developed and reads, "I will not give a fatal draught to anyone if I am asked, nor will I suggest any such thing." Through the lens of the Hippocratic Oath, euthanasia by means of a fatal draught was forbidden. However, one of the most famous examples of deviation from this code occurred when the physician of Seneca, a philosopher and tutor of Nero, provided the scholar, who was 69 years old at the time, with poison for one of his many failed attempts at suicide.
The societies of antiquity viewed suicide and euthanasia very differently from modern culture. Although factors such as better medical and psychological insight have affected contemporary society's view of suicide and euthanasia, much of the shift in opinion of these forms of death occurred because of the change in religion—that is, Greco-Roman society was dominated by pagan religions that did not categorically condemn suicide and euthanasia.
Many modern Christians do not accept the practice of suicide or senicide, holding that only God should have control over a person's life and death.
The Heruli were a Germanic tribe during the Migration Period (about 400 to 800 CE). Procopius states in his work The Wars, that the Heruli placed the sick and elderly on a tall stack of wood and stabbed them to death before setting the pyre alight.
In the southern Indian state of Tamil Nadu, the illegal practice of senicide – known locally as thalaikoothal – is said to occur dozens or perhaps hundreds of times each year. It seems as if the old ones have accepted her death already „as they also think that they have become burden for their children”. A lady from the village Subamma argues, "What else can they do if they see their parents suffering? At least they are offering their parents a peaceful death. It is an act of dignity because living like a piece of log for years is disrespectful for the elderly themselves, more than it is for us. The elderly chooses to be offered thalaikoothal, too”. Meanwhile the old custom is replaced or reinforced by lethal injections and some old people might escape the unconstitutional custom. “The practice of thalaikoothal is unconstitutional. As no one in India is allowed to commit suicide and even in euthanasia, only passive euthanasia is allowed, therefore, in no way thalaikoothal, killing old aged parents, can be practiced”.
Herodotus says of the Padeans of India:
Other Indians, to the east of these, are nomads and eat raw flesh; they are called Padaei. It is said to be their custom that when anyone of their fellows, whether man or woman, is sick, a man's closest friends kill him, saying that if wasted by disease he will be lost to them as meat; though he denies that he is sick, they will not believe him, but kill and eat him.  When a woman is sick, she is put to death like the men by the women who are her close acquaintances. As for one that has come to old age, they sacrifice him and feast on his flesh; but not many reach this reckoning, for before that everyone who falls ill they kill.
In earlier times the Inuit would leave their elderly on the ice to die. Senicide among the Inuit people was rare, except during famines. The last known case of an Inuit senicide was in 1939.
Ubasute (姥捨, 'abandoning an old woman'), a custom allegedly performed in Japan in the distant past, whereby an infirm or elderly relative was carried to a mountain, or some other remote, desolate place, and left there to die. This custom has been vividly depicted in The Ballad of Narayama (a 1956 novel by Shichirō Fukazawa, a 1958 film, and a 1983 film).
An alleged custom was to throw incapable or ill elders off certain cliffs, a confirmed practice was the performing of euthanasia on ill, senile or suffering elders carried out by selected women named accabbadoras (lit. 'terminator' or 'ender') that after a blessing of the soon to be deceased would proceed to kill them through suffocation or blunt force to the back of the head by wooden mallet.
The Sardinian Phoenicians would use hemlock to euthanize the elderly.
In Nordic folklore, the ättestupa is a cliff where elderly people were said to leap, or be thrown, to death. While the practice has no historical evidence, the trope has survived as an urban legend, and a metaphor for deficient welfare for the elderly.
Lapot is a mythical Serbian practice of disposing of one's parents.
Parkin provides eighteen cases of senicide which the people of antiquity believed happened.:265 Of these cases, only two of them occurred in Greek society; another took place in Roman society, while the rest happened in other cultures. One example that Parkin provides is of the island of Keos in the Aegean Sea. Although many different variations of the Keian story exist, the legendary practice may have begun when the Athenians besieged the island. In an attempt to preserve the food supply, the Keians voted for all people over 60 years of age to commit suicide by drinking hemlock.:264 The other case of Roman senicide occurred on the island of Sardinia, where human sacrifices of 70-years-old fathers were made by their sons to the titan Cronus.
The case of institutionalized senicide occurring in Rome comes from a proverb stating that 60-year-olds were to be thrown from the bridge. Whether or not this act occurred in reality was highly disputed in antiquity and continues to be doubted today. The most comprehensive explanation of the tradition comes from Festus writing in the fourth century AD who provides several different beliefs of the origin of the act, including human sacrifice by ancient Roman natives, a Herculean association, and the notion that older men should not vote because they no longer provided a duty to the state.:267 This idea to throw older men into the river probably coincides with the last explanation given by Festus. That is, younger men did not want the older generations to overshadow their wishes and ambitions and, therefore, suggested that the old men should be thrown off the bridge, where voting took place, and not be allowed to vote.
Aelian writes: The Derbiccae (a tribe, apparently of Scythian origin, settled in Margiana, on the left bank of the Oxus) kill those who are seventy years of age. They sacrifice the men and strangle the women.
Herodotus tells us about the Massagetae that: "Though they fix no certain term to life, yet when a man is very old all his family meet together and kill him, with beasts of the flock besides, then boil the flesh and feast on it. This is held to be the happiest death; when a man dies of an illness, they do not eat him, but bury him in the earth, and lament that he did not live to be killed."
Works of fiction which have dealt with senicide include:
- Dinosaurs 1991 episode "Hurling Day"
- The Old Law, a 17th-century tragicomedy written by Thomas Middleton, William Rowley, and Philip Massinger
- Anthony Trollope's 1882 dystopian novel, The Fixed Period
- Jack London's 1901 short story, The Law of Life
- Keisuke Kinoshita's The Ballad of Narayama (1958)
- Shōhei Imamura's The Ballad of Narayama (1983)
- Korean director Kim Ki-young's Goryeojang (1963)
- Shohei Imamura's The Ballad of Narayama, which won the Palme d'Or in 1983.
- Christopher Buckley's 2007 novel Boomsday.
- Isaac Asimov's novel Pebble in the Sky
- Star Trek: The Next Generation, the episode "Half a Life"
- The Giver by Lois Lowry
- The Tripods, a series of young adult fiction novels by John Cristopher
- Norsemen, a Norwegian comedy TV series
- Midsommar, a film by Ari Aster
- K.D engira Karuppudurai, a Tamil language film by director Madhumitha
- Baaram or The Burden, a National Award winning Tamil language film by director Priya Krishnaswamy
- Logan's Run (film), where the definition of senecisism is at age 30
- Garland, Robert; The Greek Way of Death. (London: Duckworth, 1985) 98.
- The Guide to Life, the Universe, and Everything. BBC. “The Hippocratic Oath." 29 October 2006.
- Mystakidou, Kyriaki, Efi Parpa, Eleni Tsilika, Emmanuaela Katsouda & Lambros Vlahos; "The Evolution of Euthanasia and its Perceptions in Greek Culture and Civilization." Perspectives in Biology and Medicine, vol. 48, no. 1 (2005), 95. 21 October 2006
- Procopius, History of the Wars, Book VI, chapter XIV. Wikisource
- Magnier, Mark (January 15, 2013). "In southern India, relatives sometimes quietly kill their elders". Los Angeles Times. Retrieved January 6, 2019.
- Chatterjee, Pyali (2017). The Customary Practice of Senicide. With Special Reference to India. Grin-edition. https://www.grin.com/document/372138
- Mathew, Soumya (2016). A report on Thalaikoothal, a ritual of killing the elderly, practiced in the rural pockets of Virudhunagar district, Tamil Nadu. https://soumyamathew94.wordpress.com/2016/04/16/thalaikoothal-killing-of-the-already-withering/
- Chatterjee, Pyali (2014). Thalaikoothal. The Practice of Euthanasia in the Name of Custom. European Researcher, 2014, Vol. 87, Iss. 2, pp. 2005–12. doi:10.13187/er.2014.87.2005 http://www.erjournal.ru/en/archive.html?number=2014-11-25-17:54:26&journal=96
- Gillel, Michael. "Laudator Temporis Acti: Senicide, Part I". Retrieved 2021-03-07.
- "Did Eskimos put their elderly on ice floes to die?" The Straight Dope (May 4, 2004)
- "Senilicide and Invalidicide among the Eskimos" by Rolf Kjellstr�m in Folk: Dansk etnografisk tidsskrift, volume 16/17 (1974/75)
- "Notes on Eskimo Patterns of Suicide" by Alexander H. Leighton and Charles C. Hughes in Southwestern Journal of Anthropology, volume 11 (1955)
- Eskimos and Explorers, 2d ed., by Wendell H. Oswalt (1999)
- Winters, Riley. "The Disturbing Truth Behind a Sardonic Grin". www.ancient-origins.net. Retrieved 2021-03-07.
- Parkin, Tim G (2003). Old Age in the Roman World. Baltimore: Johns Hopkins University Press. ISBN 9780801871283. Retrieved 16 November 2019.
- Henderson, Jeffrey. "Book IV: Chapter 3". Loeb Classical Library. Retrieved 2021-03-07.
- Gillel, Michael. "Laudator Temporis Acti: Senicide, Part I". Retrieved 2021-03-07.
- Aristotle; Nicomachean Ethics (5.11)
- Plutarch. Themistocles