In ancient Rome, Celery was worn around the neck to ward off a hangover from a particularly hardy night of partying. Perhaps this is where the practice of putting a stalk of celery in a Bloody Mary. Though this has never been proven.
Celery contains the chemical 3-n butyl phthalide. This chemical allows the blood vessels to dilate. Phthalide also lowers the level of stress hormones called catacholamines.
There is an ingredient found in celery called acetylenics. Celery also contains phenolic acids.
Celery is an excellent source of potassium and antioxidant Vitamin C and dietary fiber. Celery is cholesterol free, saturated fat free and low in sodium. Celery also contains some Vitamin A, calcium and protein.
When selecting celery look for straight rigid stalks that snap when bent and leaves that show no sign of wilting.
All You Ever Wanted to Know About Celery, Vegetables and Nutrition.