There are poisons known which do not act at once, with violence.

The very first is the lethal poison known as Halahala.

It is one of the most potent poisons known.

A13 The gas used in Tokyo is among the most potent poisons known.

It is the most potent poison known to us from the entire animal world.

No blade, no poison known to man can kill me.

It also happens to be the deadliest poison known to man.

That they could take down a ship at sea loaded with two tons of the deadliest poison known to man?

Plutonium is the most deadly poison known to man.