The spleen is an organ in the upper left side of the abdomen. It
filters the blood by removing old or damaged blood cells and platelets. It also
helps the immune system by destroying bacteria and other foreign substances.
The spleen holds extra blood that can be released into the circulatory system
ByHealthwise Staff Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine Specialist Medical ReviewerW. David Colby IV, MSc, MD, FRCPC - Infectious Disease