"Black hellebore" was used by the Greek and Romans to treat paralysis, gout and other diseases, more particularly insanity. "Black hellebore" is also toxic, causing tinnitus, vertigo, stupor, thirst, anaphylaxis, emesis (vomiting), catharsis, bradycardia (slowing of the heart rate), and finally, collapse and death from cardiac arrest. Although "Helleborus niger" (black hellebore) contains protoanemonin, or ranunculin, which has an acrid taste and can cause burning of the eyes, mouth, and throat, oral ulceration, gastroenteritis, and hematemesis, research in the 1970s showed that the roots of "H. niger" do not contain the cardiotoxic compounds helleborin, hellebrin, and helleborein that are responsible for the lethal reputation of "black hellebore". It seems that earlier studies may have used a commercial preparation containing a mixture of material from other species such as "Helleborus viridis", green hellebore.