Background: Post-radiotherapy xerostomia affects a patients’ quality of life (QoL). Carboxymethylcellulose (CCMC)-based saliva substitute products have been widely used to relieve symptoms of xerostomia.

Objective: We compared subjective short-term clinical effectiveness between commercially available CCMC-based saliva substitutes (GC Dry Mouth Gel) and King Chulalongkorn Memorial Hospital (KCMH) saliva substitutes on post-radiation xerostomia related QoL.

Methods: Fifty head and neck cancer patients with post-radiation xerostomia were randomly assigned (1:1) to receive either CCMC-based saliva substitutes (CCMC group) or KCMH saliva substitutes (KCMH group) in a blinded manner. Patients returned to our clinic 14 days after treatment for follow-up assessment. Comprehensive xerostomia questionnaires were used to evaluate the clinical effectiveness of the two CCMC-based saliva substitutes. Xerostomia severity level and four major domains of xerostomia-related quality of life, before and after treatments were assessed. Primary outcomes of QoL were analyzed using an ANCOVA, adjusting for baseline differences and chi-square statistics.

Results: After the completion of 14 days treatment, mean self-rated VAS scores of xerostomia severity in the CCMC group and KCMH group were 50.1 and 59.0 mm., respectively (p = 0.04). Mean scores of the CCMC group were significantly different from the KCMH group in three continuous outcome variables, namely speech difficulty, taste alteration, and frequency of sipping water. Additionally, there was one dichotomous outcome variable, taste alteration (p < 0.05). No other significant difference was found between the groups. The proportion of patients reporting a “response” or “major improvement” from baseline in xerostomia severity and speech difficulty were significantly different between groups (p = 0.03 and 0.04, respectively).

Conclusion: Commercially available CMC-based saliva substitute showed better outcomes in improving severity of xerostomia, speech difficulty, taste alteration, and frequency of sipping water compared with KCMH saliva substitute.