Drug: BioXtra spray or mouth rinse Patients had been xerostomia due to radiation of head and neck were selected for the study. Gender, age, medical history, VAS, dichotomous questionnaire of xerostomia , and other treatment used for this disease were recorded. Local ethical committee approval was obtained before the trial started and all patients gave written informed consent. Patients were randomly divided into two groups .First group received BioXtra spray and second group used BioXtra mouth rinse for 2 weeks and then 1 weeks wash -out period and for other 2 weeks drugs is switched . Each patients was examined at the beginning of the therapy ,and then 2 weeks after therapy and 35 days after first visit.

spray /mouth rinse

change of symptoms of xerostomia is measured by Visual Analogue Scale and Dichotomos questionnaire[ Time Frame: baseline compared with measures on day 14](streamdown:incomplete-link)

change of symptoms of xerostomia is measured by Visual Analogue Scale and Dichotomos questionnaire[ Time Frame: baseline compared with measures on day 35 and comparative analysis between BioXtra spray and mouth rinse](streamdown:incomplete-link)