The amount of a chemical that is lethal to one-half (50%) of the experimental animals exposed to it. LD50s are usually expressed as the weight of the chemical per unit of body weight (mg/kg). It may be fed (oral LD50), applied to the skin (dermal LD50), or administered in the form of vapors (inhalation LD50).

A chemical does lethal to 50 percent of a test population.

Lethal dose fifty.

Dose required to kill 50% of laboratory test animals.

Short for "Lethal Dose 50." In toxicology, the amount of a substance sufficient to kill one-half of the population of test subjects (e.g., mice or rats).

LD50: (Lethal Dose 50) is the dose of a chemical which kills 50 percent of a sample population. In full reporting, the dose, treatment and observation period should be given. LD50s are strictly only comparable when the age, sex, and nutritional state of the animals is specified.

The dosage of chemicals needed to produce death in 50 percent of treated organisms. LD50s are usually expressed as the weight of the chemical per unit of body weight (mg/kg). Chemicals may be fed (oral LD50), applied to the skin (dermal LD50), or administered in the form of vapors (inhalation LD50).

(lethal dose50%)  The amount of a chemical required to kill 50% of the test population. The higher the LD50, the lower the presumed toxicity of the chemical.

The amount of a substance that is lethal to 50 per cent of the experimental animals exposed to it. LD50 is usually expressed as the weight of the substance per unit of body weight of the animal in order to account for weight difference among animals. More information about LD50 and other measures of exposure to toxic substances can be found at the following site: Dose-response relationships in toxicology (Extension Toxicology Network, USA)

The dose that is lethal to 50% of the test animals or micro organisms in a given time period. It is usually expressed in milligrams of insecticides per kilogram of body weight in mammals, and micrograms of insecticides per gram of body weight in insects. The lower the LD value, the higher the toxicity.

The dose required to produce the death in 50 percent of the exposed species within a specified time.

Lethal dose 50. The median dose of a material, by any route but inhalation that kills 50% of a group of test animals. Usually expressed as milligrams or grams of material per kilogram of animal weight.

A calculated dose of a chemical in water to which exposure for a specific length of time is expected to cause death in 50% of a defined experimental animal population.

the weight of material which causes the death in 50% of a group of test animals. It is usually expressed in weight of material per weight of test animal. LD stands for lethal dose.

the dose of a given substance that will kill 50% of a certain population. The Lethal Dose-50 has become the standard reference for summarising the toxicity of substances.

Dose Causing 50% Mortality in Bioassay

means a dose of a substance that produces death in 50 per cent of a population of experimental animals. It is usually expressed as milligrams per kilogram (mg/kg) of body weight.

(Lethal Dose): A measure of a pesticide's acute toxicity by dose. It is the quantity of a chemical sufficient to kill 50% of the test group. The chemical is usually administered as a single dose although tests that use repeat dosing are also possible. The chemical is given by injection or ingestion. The LD50 may be an observed value or, more frequently, calculated by interpolation or extrapolation. The LD50 is usually expressed in milligrams of chemical per kilogram of body weight. In birds, currently, adults are given a one-time dose and subsequently observed for at least 14 days. See LC50 and toxicity test.

The amount of a substance sufficient to kill 50% of the test animals. Also called the median lethal dose.

the dosage of a toxic substance required to kill one half of the organisms under study in a given period of time List of Glossary Terms

dosage (by ingestion or injection) killing 50% of experimental animals

Lethal dose for 50% of a given population (usually lab rats).

Lethal dose needed to kill 50% of the test population.

The dose (quantity) of a chemical(s) calculated to be lethal to 50% of the org anisms in a specific test situation. It is expressed in weight of the chemical (mg) per unit of body weight (kg) of the test organism. The toxicant may be fed (oral LD50), applied to the skin (dermal LD50), or administered in the form of vapors (inhalation LD50).

Lethal Dose” of a substance that will kill 50% of a population of organisms; this is generally expressed as milligrams of toxin per kilogram of body weight.

Lethal Dose for 50% of test subjects

Lethal Dose 50%; a single dose of material which, on the basis of laboratory tests, is expected to cause 50% mortality in a group of test animals when administered as a single exposure

See Lethal Dose50.

The amount of a substance that is required to kill one-half of the organisms under study.

The quantity of material that when ingested, injected, or applied to the skin as a single dose, will cause death of 50% of the test animals. The test conditions should be specified, the value is expressed in g/kg or mg/kg of body weight.

See LETHAL DOSE 50.

Lethal Dose 50%; a single dose of a material which, on the basis of laboratory tests, is expected to kill 50% of a group of test animals. The material may be administered orally or applied to the skin.

the dose of a chemical which kills 50% of a sample population. In full reporting, the dose, treatment and observation period should be given. Further, LD50, LC50, ED50 and similar figures are strictly only comparable when the age, sex and nutritional state of the animals is specified. Nevertheless, such values are widely reported and used as an effective measure of the potential toxicity of chemicals. (See also LC50).

50 percent lethal dose

Lethal Dose of a toxicant that will kill 50 percent of the test population. The lower the LD50, the more toxic the chemical.

the amount of substance that when fed to or applied on test animals, will kill half of the animals in the test. It is the lethal dose for 50% of the animals being tested under specific conditions.

the theoretical lethal dose for 50 per cent of a group of animals

a single dose of a material expected to kill 50 per cent of a group of test animals. The LD50 dose is usually expressed as miligrams or grams of material per kilogram of animal body weight (mg/kg or g/kg). The material may be administered by the mouth or applied to the skin.

In a toxicology study, this is the level at which a single dose causes death in half of the test animals participating in the study (acute toxicity is normally defined by LD50 values).

Lethal dosage 50%; a measure of acute toxicity. The dose of a substance expected to kill half of a group of test animals exposed for a specified period.

The dose of a chemical taken by mouth or absorbed by the skin which is expected to cause death in 50 percent of the test animals so treated.

Short for "Lethal dose 50"; the dosage of a drug or poison that is toxic to 50% of the organisms it is tested against. Often applies to does of drug against microorganisms.

In toxicology, the LD50 (abbreviation for "Lethal Dose, 50%") or median lethal dose of a toxic substance or radiation is the dose required to kill half the members of a tested population. LD50 figures are frequently used as a general indicator of a substance's acute toxicity. The test was created by J.W.