Given LD50 values of 5 mg/kg for compound A and 50 mg/kg for compound B, which statement describes their relative acute oral toxicity?

Given LD50 values of 5 mg/kg for compound A and 50 mg/kg for compound B, which statement describes their relative acute oral toxicity?

• A. Compound A is more acutely toxic than B.
• B. Compound B is more acutely toxic than A.
• C. They have equal toxicity.
• D. The LD50 cannot determine toxicity.

Answer: (A)

LD50 is the dose that will kill 50% of a test population after a single oral exposure. A lower LD50 means higher acute toxicity. Here, compound A has an LD50 of 5 mg/kg, which is ten times smaller than compound B’s 50 mg/kg. This means only 5 mg per kg is enough to reach 50% mortality for A, while it takes 50 mg per kg of B to cause the same effect. So compound A is more acutely toxic than compound B. The idea that they have equal toxicity is incorrect, since the LD50 values differ, and LD50 specifically reflects acute toxicity (not chronic effects or other toxic endpoints).

LD50 is the dose that will kill 50% of a test population after a single oral exposure. A lower LD50 means higher acute toxicity. Here, compound A has an LD50 of 5 mg/kg, which is ten times smaller than compound B’s 50 mg/kg. This means only 5 mg per kg is enough to reach 50% mortality for A, while it takes 50 mg per kg of B to cause the same effect. So compound A is more acutely toxic than compound B. The idea that they have equal toxicity is incorrect, since the LD50 values differ, and LD50 specifically reflects acute toxicity (not chronic effects or other toxic endpoints).