An oral biopsy is a procedure used to diagnose any abnormal cells in the mouth such as lumps, sores, or discolorations. It involves removing a small amount of tissue from the suspicious area and examining it in a laboratory to determine whether cancerous or precancerous cells are present. An oral biopsy is typically first numbed in the affected area before taking a sample with either scalpel or needle biopsy techniques. The results of the biopsy can help guide treatment options if any abnormalities are found.