Piperonal and other substances affect the odor of natural vanilla.

Now, do you know how that substance eventually affected many of the test subjects?

In the end, unsure about how a substance like Prozac would affect a writer's brain, he decided not to go.

Ordinarily, if a substance like a drug affects the body, the effects increase as the dose increases.

An interactive guide about how the environment, chemicals and toxic substances affect human health.

These substances affect the brain and make the depression worse over time.

She usually creates the same subject in various materials, curious about how different substances affect the final form.

Or a sense of grandiosity and belief the substance wouldn't affect him?

They've been injected with plutonium in an effort to find out exactly how the radioactive substance affects people.

It's part of an experiment to find how the substance, used in the nuclear industry and in weapons, affects people.