All parts of new year's day grass are severely toxic just like most species within the Buttercup family. Poisonings from this plant typically occur through mistaken ingestion, as it's often believed to be Butterbur scape, a popular, edible Japanese spring flower. New year's day grass contains two toxic cardiac glycosides, cymarin and adonitoxin, so it's not a wonder this plant is highly harmful. If ingestion occurs, it can cause vomiting, dysregulation of the respiratory system, and heart attack. In severe circumstances, eating new year's day grass can prove fatal. There is no evidence that this plant causes irritation when touched.