Safety Emporium for all your lab and safety needs
- An LD50 value is the amount of a solid or liquid material that it takes to kill 50% of test animals (for example, mice or rats) in one dose.
This is closely related to the LDLo value which is the lowest dosage reported to have killed animals or humans.
LC50 (50% lethal concentration) is a related term used for gases, dusts, vapors, mists etc.
The dose may be administered orally (by mouth), injection into various parts of the body (intraperitoneally or intravenously), or dermally (application to the skin). The value is usually reported along with the administration method.
Both LD50 and LDLo values state the animal used in the test. This is important because animal toxicity studies do not necessarily extrapolate (extend) to humans. For example, dioxins (of Love Canal, Times Beach, Sveso and Agent Orange fame) are highly toxic to guinea pigs and ducklings at extremely low levels, but have never been unambiguously linked to a single human death even at very high levels of acute (short term) exposure; note, however they are listed by IARC as "known human carcinogens". However, it is best to err on the safe side when evaluating animal toxicity studies and assume that most chemicals that are toxic to animals are toxic to humans.
Typical units for LD50 values are milligrams or grams of material per kilogram of body weight (mg/kg or g/kg, recall that 1 kg = 2.2 pounds).
Never be exposed to an LD50 dose of a hazardous chemical -- by definition, there is a 50% chance this will kill you...and if you survive you're not going to be in good shape.
Pay close attention to the permissible exposure level (PEL) instead. This is a more realistic determination of the maximum safe exposure to a material and is usually based on the known effects of the chemical on humans rather than laboratory animals.
See also: intraperitoneal, intravenous, LC50, mus (mouse), PEL, STEL, TLV.
Additional definitions from Google and OneLook.
Entry last updated: Thursday, June 25, 2015. This page is copyright 2000-2015 by ILPI. Unauthorized duplication or posting on other web sites is expressly prohibited. Send suggestions, comments, and new entry desires (include the URL if applicable) to us by email.
Disclaimer: The information contained herein is believed to be true and accurate, however ILPI makes no guarantees concerning the veracity of any statement. Use of any information on this page is at the reader's own risk. ILPI strongly encourages the reader to consult the appropriate local, state and federal agencies concerning the matters discussed herein.