Celery, Apium graveolens L is cultivated for its seeds and essential oil. An improved method has been developed for maximum yield of essential oil with higher content of phthalides (the valuable constituent of oil ), in short time, making the process economical. The method involves hydro distillation. In India Celery, Apium graveolens L is mostly cultivated in Punjab, Haryana, and U. P. for its seeds. The seeds are used as spice to flavour soups, salad, tomato juice and sauces and for extracting essential oil or oleoresin. Of late they have attained ever increasing popularity among food products. Indian celery is considered to be best in the world and that is why it is in great demand in European countries. In 1999-2000, 4038 MT of seeds worth Rs.9.5 crores and its oleoresin 146.5 MT worth Rs. 4.5 crores were exported. Oleoresin is prepared by extracting the celery seeds with volatile solvents like alcohol and driving off the alcohol in vacuo. On steam distillation it yields pale yellow essential oil with characteristic rich long lasting spicy odour, the principal components of which are d-limonene and saline. The oil is used for flavouring food products, liquors and pharmaceutical preparations. Celery is recommended for rheumatic arthritis, antispasmodic, aphrodisiac, nerve stimulant and hypertension. It also induces mensuration in non pregnant woman. It is better known as a medicinal herb than a garden vegetable. The important constituents of its essential oil are phthalides which impart medicinal value to the oil and possess strong characteristic celery aroma. The major phthalides being 3-butyl phthalide, 3-butyl tetrahydrophthalide or sedanolide, and apiole. Others being 3-butyl –4-5-dihydrophthalide or sedananolide. These form high boiling constituents of the oil besides the low boiling monoterpene hydrocarbons e.g. α –pinene,α -terpinene,γ -terpinene, β -pinene, limonene etc. The conventional process gives a yield of 1.3 to 1.8% of oil in 36 hours with phthalides content of 10 to 12%. The method used here gives a yield of 2.44-2.68% in 4-4.5 hours and the phthalides content in the oil 23 + 2%.