Several of the species are extremely poisonous, the active poison being oenanthotoxin. The most notable of these is O. crocata, which lives in damp, marshy ground, and resembles celery with roots like a bunch of large white carrots. The leaves may be eaten safely by livestock, but the stems, and especially the carbohydrate-rich roots are much more poisonous. Animals familiar with eating the leaves may eat the roots when these are exposed during ditch clearance: one root is sufficient to kill a cow, and human fatalities are also known. It has been referred to as the most poisonous of all British plants,[5] and is considered particularly dangerous because of its similarity to several edible plants.[6]
The species O. javanica, commonly known as Chinese celery or Japanese parsley (seri; not to be confused with mitsuba or Japanese wild celery, Cryptotaenia japonica) is edible and grown in several countries of eastern Asia, as well as in Italy and India, where the spring growth is relished as a vegetable.
Sardonic grin[edit]
Scientists at the University of Eastern Piedmont wrote that they had identified hemlock water dropwort (Oenanthe crocata) as the plant responsible for producing the sardonic grin.[14][15] This plant is a possible candidate for the "sardonic herb", which was a neurotoxic plant referred to in ancient histories. It was purportedly used for the ritual killing of elderly people and criminals in Nuragic Sardinia, in which they were intoxicated with the herb and then dropped from a high rock or beaten to death.[11][16]
