Here is another dangerous herb to stay away from!  This time, both internally and externally!

American hellebore ( or black and green): This herb is highly toxic and causes severe side effects, even in small doses, including reduced blood pressure and heart rate.

Internally violently narcotic that affects the heart..it can kill. Symptoms of hellebore poisoning include salivation, nausea, vomiting, colic, diarrhea, weak heartbeat, vertigo, ringing ears, disturbed vision, coronary arrest. Green hellebore is a cardiac depressant...black hellbore is a cardiac stimulant. Applied locally, the fresh root is an irritant.