Aethusa cynapium (fool's parsley, fool's cicely, or poison parsley) is an annual (rarely biennial) herb in the flowering plant family Apiaceae, native to Europe, western Asia, and northwest Africa. It is the only member of the genus Aethusa. It is related to hemlock and water-dropwort, and like them it is poisonous, though less so than hemlock. It has been introduced into many other parts of the world and is a common weed in cultivated ground.
Description
left|thumb|Inflorescence of fool's parsley
Aethusa cynapium has a fusiform root and a smooth hollow branched stem growing to about high, with much divided (ternately pinnate) smooth leaves with an unpleasant smell, and small compound umbels of small irregular white flowers.
It has three accepted subspecies according to Plants of the World Online:
Chemical composition, toxicity and medical uses
A. cynapium is poisonous when fresh, but safe if dried. A. cynapiums toxic effects are caused at least in part by cynopine, which resembles coniine in its physical and chemical characters as well as physiological actions. The whole plant is toxic with this alkaloid. Toxins like cynopine are destroyed by drying. A. cynapium also contains trideca-7,9,11-trienoic acid, aethusin, aethusanol A, aethusanol B, as well as flavone glycosides such as rutoside, narcissine, and ascorbic acid.
The parts of A. cynapium that grow above the ground are sometimes used to make medicine. The plants has been used in traditional medicine to treat complaints in children, infantile cholera, summer diarrhea, convulsions, mental tension, sleep disorders, delirium, and as stomachic. A. cynapium has actually been shown to cause antianxiety effects in mice because it contains trideca-7,9,11-trienoic acid.