I would say that there is no safe dose of the chemical Iodine that has the word "poison" on the label.
I've recently responded on another forum, to two people who posted about the negative side effects that they had after taking Lugol's iodine. And that's only in the past few days. Who knows how many other people like that are out there?
The minerals that the body needs are required in tiny amounts. That's why they're called Trace Minerals. They should be together with other compounds required for them to be properly used in the body. Only nature can provide this perfect balance. This is why I will only use plant iodine.