Probably the most poisonous plant we have in this country, always one to watch out for although it's not very common unless you're beside a particularly wet or damp area
often confused with wild celery when you look at the stem you can see why but the umbels are quite distinctive
there are many reports of people being poisoned by this plant and even more of poisonings in animals, the mortality rate for humans after ingesting this plant is 70% so it shows you how positive you must be in identifying any umbelifer..
A few stories I know of are a man once ate wild duck eggs and nettles and "wild celery", 40 mins later he was convulsing seriously and required immediate medical intervention, he continued to convulse on and off for a further 10 days although in this instance he survived he continued to have prolonged medical problems.
The main "poison" in HWD is called oenanthotoxin and in one case a man died after ingesting just 1 mg of this toxin,so please ,please be careful with all umbels.