报道了采用昆明种小白鼠,用茶汤灌胃法对三个云南产不同年份的普洱茶产品和云南大叶烘青绿茶的急性毒性对比研究结果,三个普洱茶样品的LD₅₀分别为：9.7βg/kg、11.2βg/kg、12.2βg/kg,而测得烘青绿茶的LD₅₀为7.5βg/kg。并发现四个样品的一次灌胃量在5βg/kg以下时喂养观察十四天没有动物死亡,1/2LD₅₀以下的灌胃量灌胃后多数动物表现出神经兴奋症状;随着灌胃剂量加大,动物在10βmin后出现神经抑制症状。三个普洱茶样的急性致死时间只有一个高峰期,而烘青绿茶则有两个死亡高峰期,死亡原因是由过高浓度的咖啡碱和茶多酚有关,从LD₅₀来看,两类茶叶的食用安全性都很高,但科学的饮茶法是饮茶健身的必然要求。

The acute toxicity of three kinds of typical Pu’er tea and one kind of baked green tea from Yunnan province were evaluated in this investigation. The tested mice were feed with tea infusion. The LD₅₀ of the three kinds of Pu’er Tea was 9.7βg/kg, 11.2 βg/kg and 12.2 βg/kg respectively, while that of the baked green tea was 7.5βg/kg. None of tested mice died 14 days later, when single feeding dose of four kinds of tea was less than 5βg/kg. Most tested mice showed excitement when the feeding dose less than 1/2 of LD₅₀. The tested mice revealed symptoms of restrained nervous 10 minutes late with the feed dose increased. There was only one peak of the acute lethal time in the case of Pu'er tea, and two peaks appeared in the case of baked green tea. The authors regarded that the death of tested mice was attributed to the high concentration of caffeine and polyphenols. It is concluded that all four kinds of tea are highly safe for drinking according to LD₅₀. However , scientific drinking methods should be mentioned first.