Among chemicals there is a wide spectrum of doses needed to produce deleterious effects, serious injury, or death. The median lethal dose, LD50 (abbreviation for “lethal dose, 50%”), LC50 (lethal concentration, 50%) or LCt50 is a measure of the lethal dose of a toxin, radiation, or pathogen.
- The value of
LD50for a substance is the dose required to kill half the members of a tested population after a specified test duration. LD50figures are frequently used as a general indicator of a substance’s acute toxicity. A lowerLD50is indicative of increased toxicity.
It should be noted, however, that measures of acute lethality such as LD50 do not accurately reflect the full spectrum of toxicity, or hazard, associated with exposure to a chemical.