India, a major supplier of many drug ingredients to the U.S., has already limited exports of the painkiller acetaminophen.

印度是美国许多药品成分的主要供应国，已经限制了止痛药扑热息痛的出口。

They're estimated after seeing how samples of a drug degrade over short periods of time, or by accelerating the breakdown of the drug's active ingredients.

他们先在短期内观察药物样本的降解，或通过加速药物活性成分分解，然后预估出保质期。

They're estimated after seeing how many samples of a drug degrade over short periods of time, or by accelerating the breakdown of the drug's active ingredients.

他们先在短期内观察药物样本的降解，或通过加速药物活性成分分解，然后预估出保质期。

But in the 70s and 80s, the FDA said that drug ingredients already on the shelf could stay if they were generally recognized as safe and effective by medical professionals.

但在上世纪七八十年代，美国食品及药物管理局表示，已经摆在货架上的药物成分，如果被医学专家普遍认为是安全有效的，就可以继续保留。