LD50 (Median Lethal Dose)
At a glance: The single dose expected to kill half of a test population.
The LD50, or lethal dose 50%, is the dose required to kill half the members of a tested population after a specified test duration. It is widely used as a general indicator of acute toxicity: a lower LD50 indicates greater toxicity. 28 It is expressed as the weight of chemical per kilogram of body weight, with the test species and route stated—for example, LD50 (oral, rat) 5 mg/kg. 29 LD50 values underpin acute-toxicity hazard categories in GHS. The inhalation equivalent is the LC50.