Index of acute toxicity: LD50 LDso is the lethal dose for 50% of a population Toxicant A Toxicant B 0 Log Dose Illustration of a dose-response curve in which the response is the death of the organism; the cumulative percentage of deaths of organisms is plotted on the y-axis Dose is expressed as the weight of a chemical consumed by an experimental animal per kg of body weight of the animalIndex of acute toxicity:LD50 LD50 is the lethal dose for 50% of a population. Dose is expressed as the weight of a chemical consumed by an experimental animal per kg of body weight of the animal