This study assessed the efficacy of the Bioxtra (BX) and Biotène Oralbalance (OB) systems in the treatment of post‐radiotherapy xerostomia. In a double‐blind, crossover study, 20 patients with post‐radiotherapy xerostomia were randomly allocated to receive either OB then BX, or vice versa, each product for 2 weeks, with a 1 week wash‐out period in between. Subject‐based dry mouth scores derived from 100‐mm visual analogue scales were recorded at days 0 and 14 of each 2‐week period, together with subjective perception of changes in dry mouth symptoms. Both treatments were effective, resulting in reduction of visual analogue scale scores from day 0–14. Between‐groups comparisons identified that BX achieved significantly better improvements compared with OB for the perception of dry mouth and improvements in speech and was also rated as more pleasant to use than OB (P < 0.05). In conclusion, both treatments were effective in alleviating the symptoms of post‐radiotherapy xerostomia, although BX achieved superiority in some of the outcomes assessed compared with OB.