The name LD50 is an abbreviation for "Lethal Dose, 50%" or median lethal dose. It is the amount of the substance required (usually per body weight) to kill 50% of the test population.
The test was created by J.W. Trevan in 1927 but has been phased out. The U.S. Food and Drug Administration has begun to approve non-animal alternatives to LD50, in response to research cruelty concerns and the lack of validity/sensitivity of animal tests as they relate to humans.
- Oral LD50 of grain alcohol: 10.6 g/kg in young rats, 7.06 g/kg in aged rats.
- Oral LD50 of nicotine: 50 mg/kg in rats.
- Oral LD50 of Table Salt: 3000 mg/kg in rats 
- LD50 of Delta-9-tetrahydrocannabinol (THC) (active ingredient found in Cannabis): Fischer rat, oral 1,270 mg/kg 1.270
- LD50 of smoked and inhaled Cannabis or Marijuana: Unknown. At present it is estimated that marijuana's therapeutic index is around 1:20,000 or 1:40,000 (the "1" in the prior estimate is based on an "effective dose" of the .9 grams contained in NIDA-supplied marijuana cigarettes, although the potency of Cannabis changes based on the genetics of the source plant) placing its LD50 around at least 18,000g.
- What is an LD50 and LC50
- LD50 test ban welcomed
"Allergan Receives FDA Approval for First-of-Its-Kind, Fully in vitro, Cell-Based Assay for BOTOX® and BOTOX® Cosmetic (onabotulinumtoxinA)". Source: Allergan, Inc. News Provided by Acquire Media. Page last updated 24 June 2011. Retrieved 2011-06-26. Check date values in:
"In U.S., Few Alternatives To Testing On Animals". Washington Post. Page last updated 12 April 2008. Retrieved 2011-06-26. Check date values in:
- Alcohol Chemistry
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