The LD50 value refers to the dose required to kill what proportion of a test animal population?

The LD50 value refers to the dose required to kill what proportion of a test animal population?

• A. 25%
• B. 75%
• C. 0%
• D. 50%

Answer: (D)

LD50 is the median lethal dose—the amount of a substance that would kill half of a test population under the specified conditions. It’s derived from a dose–response curve and used to compare acute toxicities across substances. The essence is that about 50% of the animals would die at that dose, so it’s a representative standard measure of toxicity. Other percentages describe different points on the curve (like a dose that kills 25% or 75%), but the LD50 specifically corresponds to 50% mortality.

LD50 is the median lethal dose—the amount of a substance that would kill half of a test population under the specified conditions. It’s derived from a dose–response curve and used to compare acute toxicities across substances. The essence is that about 50% of the animals would die at that dose, so it’s a representative standard measure of toxicity. Other percentages describe different points on the curve (like a dose that kills 25% or 75%), but the LD50 specifically corresponds to 50% mortality.