LD_(50)是标志药物毒力的重要定量指标。在经典方法中,常用动物的死亡概率来计算LD_(50)值,动物需要量大。1949年,Beccari提出了一种只用10只左右的动物来计算 LD_(50)的新方法。通过测定一个动物的存活时间(Survival time)和从毒性作用中康复的时间(Recovery time),来估测 LD_(50)值。他发现所用药物剂量与存活时间为一双曲线关系,而 LD_ (50) is an important quantitative indicator of drug toxicity. In the classical method, the LD 50 value is often used as the death probability of an animal, and the animal needs are large. In 1949, Beccari proposed a new method of calculating LD_ (50) using only about 10 animals. The LD 50 value was estimated by measuring the Survival time of one animal and the recovery time from toxic effects. He found that the dose of the drug used was a hyperbolic relationship to the survival time