Dry mouth is a very common complaint for many undergoing chemotherapy and head, neck, and mouth radiation. Dry mouth can affect eating and can eventually lead to unwanted weight loss. Mouth Sores (also known as oral stomatitis) can be a side effect of some IV and oral chemotherapies as well as immunotherapies. Swishing daily with a mixture of L-glutamine powder and water can be effective in the treatment and prevention of this condition.