Alkanet

This thick red-brown leaves plant does not like bright light and grows in thick forests. Its leaves look like a brown cabbage from a distance but, if these are edible, it is especially the roots of this plant that are sought after for its anti-poison effects.
This concoction grants advantage on saving throws against all Ingested poisons for the next 8 hours, and on saving throws to negate the poisoned condition and any other effects from an Ingested poison that has been absorbed into the hour preceding the consumption of the beverage. The subject does not, however, recover any hit points lost due to the poison.