Certain substances produce light when they are illuminated by more energetic radiation, a process known as fluorescence.

This solution contains prostaglandin, a substance produced naturally in the body.

This time the substance he tossed onto the fire produced a huge puff of lemon-colored smoke.

The substance reacts with the aluminum foil and produces the heat.

Those other substances apparently don't produce the same painful aftereffects.

But under these conditions, even harmless substances produce such damage.

These substances produce a mild irritation when applied to the skin, he said.

These substances produce a sedative and anxiety-reducing effect, which can lead to dependence.

The substances your brain produces depend in part on your thoughts, feelings, and expectations.

The blood has also absorbed substances produced from our food.