Lethal dose

A lethal dose (LD) is an indication of the lethality of a given substance or type of radiation. Because resistance varies from one individual to another, the 'lethal dose' represents a dose (usually recorded as dose per kilogram of subject body weight) at which a given percentage of subjects will die.

Related Topics:
Lethality - Radiation

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The most commonly-used lethality indicator is the LD50, a dose at which 50% of subjects will die. LD measurements are often used to describe the power of venoms in animals such as snakes.

Related Topics:
LD50 - Snakes

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Animal-based LD measurements are a commonly-used technique in drug research, although many researchers are now shifting away from such methods.

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LD figures depend not only on the species of animal, but also on the mode of administration. For instance, a toxic substance inhaled or injected into the bloodstream may require a much smaller dosage than if the same substance is swallowed.

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