哈利波特在三强争霸赛结束之后为什么不用当众喝吐真剂的方式证明伏地魔回来了？ 第1页

关于问题的回答：这是一个zz问题，而不是一个刑事问题。

关于问题补充里的回答：就好像为什么法院判案不用测谎仪一样。

JKR曾经回答过吐真剂的局限性，归纳下来就是：1部分人有抗性 2即使没有抗性，服用者也只会诚实的说自己所相信的东西（但这不一定是真实的）。

potter wiki原文如下：

Since some wizards and witches can resist its effects while others cannot, Veritaserum is "unfair and unreliable to use at a trial" and would be difficult to use as definite proof of guilt or innocence.

Another problem is that the victim states what only they believe to be true, so the victim's sanity and perception of reality are also factors in during interrogations. Therefore, while the drinker's answers are sincere, they are not necessarily true.