Celery Seed Extract 85% 3nB 60 caps by Natural Factors contains an 85% composition of a compound in fresh celery known as 3-n-butylphthalide which helps to support and strengthen the circulatory system. Just one capsule is the equivalent of consuming 6 ribs of celery. Celery Seed Extract helps to lower blood pressure levels. aids in reducing water retention in the body. and helps those suffering with arthritis feel less pain in their muscles and joints.