How do you know there aren't unknown side effects that'll kill you?

Then Kirk knew that it was they who were dissolving in some unknown effect.

We have introduced large quantities of new chemicals into the environment, often with unknown effects.

There are unknown effects on human health that also need to be considered.

Megan, then 10 months old, became Michael's donor, even though it would probably make him a carrier of the disease with an unknown effect.

Yet the government warns that the drugs may be fatal to some older patients and have unknown effects on children.

Another mutation in the same sample at position 153 has as yet unknown effects.

America takes a leap into the unknown on Tuesday as major provisions of the new welfare law take effect.

Potential but unknown ill effects are what concerns some medical people.

I'm very worried about using supplements that may have unknown side effects.