Celery — Apium graveolens is a plant species in the family Apiaceae, and yields two important vegetables known as celery and celeriac. Cultivars of the species have been used for centuries, whilst others have been domesticated only in the last 200-300 years. The petiole is the part consumed.
n temperate countries, celery is also grown for its seeds, which yield a valuable volatile oil used in the perfume and pharmaceutical industries. Celery seeds can be used as flavouring or spice either as whole seeds or, ground and mixed with salt, as celery salt. Celery salt can also be made from an extract of the roots. Celery Salt is used as a seasoning, in cocktails (notably to enhance the flavour of Bloody Mary cocktails), on the Chicago-style hot dog, and in Old Bay Seasoning.
There is a common belief that celery is so difficult for humans to digest, that it has ‘negative calories’ because human digestion burns more calories than can be extracted. Snopes believes this to be true, however at only 6 calories per stalk, the effect is negligible. Celery is still valuable in diets, where it provides low-calorie fiber bulk. Celery contains androsterone. Bergapten in the seeds can increase photosensitivity, so the use of essential oil externally in bright sunshine should be avoided. The oil and large doses of seeds should be avoided during pregnancy: they can act as a uterine stimulant. Seeds intended for cultivation are not suitable for eating as they are often treated with fungicides.