A drug is a chemical substance.

毒品是一种化学物质。

youdao

A molecule is the smallest part of a chemical substance.

分子是化学物质的最小的部分。

youdao

A chemical substance that prevents or slows a cathodic or reduction reaction.

一种阻止或减缓阴极反应的化学物质。

youdao

Now that's pretty far fetched and not many people would say that a pop tart should be a controlled substance and regulated by government, but there are some very interesting chemical properties associated with foods like this that trigger things going on in the brain that affect us in a very big way.

这多少有点牵强,而且也没有很多人会认为,这种果酱馅饼应归为管制品,并受到政府监管,但有趣的是这种食品,确实有一些特别的化学特性,它会作用于大脑并会对我们产生大的影响

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

Apparently the microwavable pad housed a chemical substance (manufactured by ADEKA) not quite stable enough to handle the heat, sparking a lengthy list of of cases where the liquid erupted from its container and provided an uncomfortable surprise to the poor soul embracing the creature's volcanic warmth.

ENGADGET: Exploding Hello Kitty toys recalled

For instance, Merck and Pfizer spent years trying to develop drugs that worked on a mysterious brain chemical called substance P.

FORBES: Antidepressant Foods

This can turn a non-toxic substance called 5-fluorocytosine into a nasty chemical called 5-fluorouracil that kills all cells, normal and malignant.

ECONOMIST: Cancer treatment