<p>To evaluate the effect of diode laser photobiomodulation in the treatment of xerostomia among diabetics.&#xa0;A randomized controlled clinical trial was conducted on 52 diabetic patients experiencing xerostomia. Participants were randomly assigned to a test group, receiving diode laser application or to a control group, receiving no active treatment. Unstimulated and stimulated salivary flow rates were assessed at baseline, 2, 4, 6 and 12 weeks. Subjective xerostomia symptoms were evaluated using the Xerostomia Inventory.&#xa0;In the test group, unstimulated salivary flow rose from 0.13 ± 0.04 mL/min at baseline to 0.25 ± 0.06 at week 12, and stimulated flow from 0.51 ± 0.09 to 1.00 ± 0.27 (<i>p</i> &lt; 0.001 for both). Unstimulated flow in the control group increased from 0.12 ± 0.05 to 0.14 ± 0.05, and stimulated flow from 0.48 ± 0.10 to 0.54 ± 0.11, with significance detected only at week 12. Subjective xerostomia scores also improved in the test group, decreasing from 12.19 ± 2.02 to 8.48 ± 1.83 (<i>p</i> &lt; 0.001), while no significant change was noted in the control group.&#xa0;Photobiomodulation with a 980&#xa0;nm diode laser might be an effective and safe therapeutic modality to improve salivary flow and xerostomia symptoms in diabetic patients.</p><p><i>Trial registration</i>:The study has been registered at ClinicalTrials.gov (NCT06703372), 22/11 2024</p>