Normally a balance of bile salts, lecithin and cholesterol prevents gallstones from forming. If there are abnormally high levels of bile salts or, more commonly, cholesterol, stones can form. Symptoms usually occur if stones block one of the biliary ducts. Gallstones may also be discovered upon ultrasound or abdominal CT study.
Reviewed By: Emily Wax, RD, The Brooklyn Hospital Center, Brooklyn, NY. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.