A dose the size of a few grains of table salt can kill an adult human.

It is not difficult to get hold of phosphorus, and a very small dose will kill.

A large enough dose could kill, but the gas was easy to detect by scent and sight.

Small dose together might even have killed her, but here there was no chance.

A large direct dose can even kill them.

"A direct dose of this stuff could kill him."

"Did you know that a double dose would kill him?"

A full dose of it could kill a strong man in a few seconds.

Very high doses of Essiac killed the test animals.

In other words, a dose sufficient to help you could just as easily kill you.