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CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

LD₅₀

The dose, in mg per kg of body mass, that kills half of a test population (usually rats). It measures acute toxicity: a lower LD₅₀ means a more toxic substance.

Dose–response curvePercentage of a test population killed against dose on a logarithmic scale. The curve is S-shaped; the LD₅₀ is the dose that kills 50 %, here 10 mg per kg of body mass. A lower LD₅₀ means a more toxic substance.0.11101001000050100dose (mg per kg body mass, log scale)% of population killedLD₅₀50 %

LD₅₀ is read off where the curve crosses 50%.

Example

Vitamin C (LD₅₀ 11,900 mg/kg) is about 60 times less acutely toxic than caffeine (192 mg/kg), since 11,900/192≈6211{,}900 / 192 \approx 62.

See alsoDoseToxicity