Large doses, over time, can lead to such side effects as anxiety, paranoia and heart problems, medical experts say.

High doses of mineral supplements can also lead to side effects and toxicity.

High doses of vitamin A in pregnancy can lead to birth defects, it said.

In those cases, the higher doses can lead to the potential for more side effects.

Conversely, a large dose may lead to very small amounts of propranolol in the blood.

Those higher doses, in turn, lead to even less sensitive synapses.

A high enough dose of Anectine led to cardiac arrest.

This bigger dose of male fern could lead to more serious side effects.

A poisonous dose may lead to a coma or death after 24 hours.

It is unlikely that this dose would lead to liver failure.