Ancient Ayurvedic medicine practitioners used celery seed to treat water retention, colds, digestive problems, flu, arthritis, and liver and spleen disorders. Today’s most common herbal use for celery is celery seed diuretic, although it is also used for a variety of other common ailments and health issues. Common celery seed oil uses in herbal medicine are listed below:
Celery seeds contain a compound, 3-n-butylphthalide, that has been demonstrated to lower blood pressure in rats. 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, as they can act as a uterine stimulant. Seeds intended for cultivation are not suitable for eating as they are often treated with fungicides.
Celery is used in weight-loss diets, where it provides low-calorie dietary fibre bulk. Celery is often purported to be a "negative calorie food" based on the idea that the body will burn more calories during the digestion of the food than the body can extract from the food itself. The fact that the body uses very small amounts of energy in digestion compared to what can be extracted even from a low calorie food like celery disproves this theory.