A hemicolectomy is a type of surgery where part of the colon (large intestine) is removed. Depending on which part of the colon is affected, the surgery can be a right hemicolectomy, or left hemicolectomy. The colon plays a key role in digestion, by absorbing water and electrolytes, solidifying waste, and eliminating it from the body so removing a portion of it is usually done to treat serious conditions like cancer, blockages, or severe inflammation.