lethal dose; fatal dose
The amount of a substance (drug, poison, radiation, etc.) that causes death. Often used in medical, toxicological, and forensic contexts.
The lethal dose of this drug is 10 milligrams per kilogram of body weight.
Exposure to a lethal dose of radiation causes death within a few weeks.
The blood concentration of the drug reached a lethal dose.
The amount ingested exceeded the lethal dose.
He accidentally ingested a lethal dose of sleeping pills.