Not to be semantically confused with : Fairy Flax (Linum catharticum), Rescue Brome (Ceratochloa cathartica), nor with species of Buckeye such as Yellow Buckeye (Aesculus flava) nor with Buck's-Beard (Aruncus dioicus), Buckwheat (Fagopyrum esculentum) or Buck's-horn Plantain (Plantago coronopus) [differing species belonging to widely differing families with similar names]

Can be confused with : Other Buckthorns, some of which belong in a different Genus, Frangula, but both genera belong in the same Family Rhamnaceae:

No relation to : Sea-Buckthorn (Hippophae rhamnoides) a spiny shrub found near the sea with bright orange berries [a plant with similar name belonging to a differing family].

If the berries are consumed, they are mildly toxic, causing almost immediate violent stomach cramps, regurgitation and a laxative effect. It is said that both an Aglycone AnthraQuinone (without any glucosides) and Emodin in the berries are responsible for these symptoms. Emodin acts as an anti-microbial protecting the fruit from bacterial and fungal attack. The concentration of emodin diminishes as the fruit ripens. The specific epithet cathartica eludes to these properties. It could be that the mild toxins dissuade birds from eating the unripe berries, but allow them to eat ripe berries without too much trouble. Buckthorn is distributed by birds after consuming the fruit and subsequently excreting the seeds undigested.

It is found especially on lime soils in scrub, hedges, woods and fens but also on peat soils. It is native.