Definition
The dose of a toxicant that will kill 50% of test organisms within a designated period of time. The lower the LD 50, the more toxic the compound.
See also:
Acute Effect
An adverse effect on any living organism in which severe symptoms develop rapidly and often subside after the exposure stops.
Acute Toxicity
Adverse effects that result from a single dose or single exposure of a chemical; any poisonous effect produced within a short period of time, usually less than 96 hours. This term normally is used to describe effects in experimental animals.
Chronic Effect
An adverse effect on any living organism in which symptoms develop slowly over a long period of time or recur frequently.