<s>[INST] My Father-Inlaw finished Throat Cancer treatment a year ago this November. However, he cannot produce saliva anymore, but when he is full from eating, his nose runs. He is convinced that somehow scar tissue is built up around his saliva glands and re-routing it through his nose. Is this possible? And can dry mouth be fixed surgically? [/INST] Hi there, Radiation causes what we call as 'xerostomia' or dry mouth. Most of the patients learn to live with it with help of water. Alternatively you could ask your radiation oncologist to prescribe saliva substitutes whichever are available in your country.  I feel if he is not swallowing correctly because of which he may be regurgitating which can happen after radiotherapy. Unfortunately no surgical options are offered for these problems. Take care </s>