<qa>  What will patients respond to citric acid receive a hypnotic session with specific suggestion10 head and neck cancer patients with xerostomia following radiotherapy will be assessed for severity of xerostomia using questionnares and quantitative salivation tests. patients responsive to citric acid will receive a hypnotic session with specific suggestion for salivation. saliva volume will be assessed pre and post hypnosis. patients will receive a CD with recorded hypnotic session to use freely at home. xerostomia will be assessed using a questionnare one week following hypnosis. 