The spleen is a brownish fist-sized organ located in the upper left side of the abdomen, tucked into a space between the stomach, pancreas and left kidney. It’s one of those organs that people know about, but aren’t sure what it does. Essentially, the spleen is a storage container and filter for blood, though it is part of the lymphatic system. In fact, it’s the largest lymph node in the body. One of its tasks is to remove harmful bacteria and viruses in the blood stream. Its other major task is removing or storing certain blood cells. The spleen is not part of the digestive system however is connected to the blood vessels of both the stomach and the pancreas.