Hemlock poisoning

Merlin used hemlock to poison Morgana after he finds out that she is the source of magic making camelot go to sleep, he took it from Giaus's chamber and mixed it with water, Morganna, unkowingly drank the water, getting poisoned by the hemlock after Morgause heard her scream she rushed to her and brought her to a safe place, nobody yet knows if Morgana suvived or not.