Background: Dry mouth is a common perioperative patient complaint. There are a number of treatments used for dry mouth in other settings which are effective. None have been tested previously in the perioperative setting. Interventions to Manage Dry mouth (IM DRY) compared the effect of water and a saliva substitute on mouth dryness. The primary objective was to demonstrate the feasibility of conducting a large randomised controlled trial and secondary scientific aims were to assess treatment potential efficacy. Methods: Single blind, pilot randomised controlled trial (RCT) of 101 pre-operative elective surgical patients who were randomised to water or saliva substitute (Biotene oral rinse, GlaxoSmithKline, Australia) at a tertiary, university hospital. Dry mouth was assessed by 100 mm visual analogue scale (VAS) and 5-point Likert score. Results: One hundred participants completed follow-up and comprised the analysis dataset. All feasibility outcomes were achieved (recruitment rate > 5 participants a week, >95% completeness of the dataset, study protocol acceptability to staff, acceptability to participants > 66% and adherence to time limits within the protocol). Mean recruitment rate was 6 participants per week. These data were 99% complete. There were no adverse side effects or complications noted. There were no concerns raised by staff regarding acceptability. Overall, there was a mean of 30 min (± SD 5 min) between delivery of the intervention and the assessment, 30 min being the target time. The difference in VAS post intervention was − 11.2 mm (95% CI − 17.3 to − 5.1 mm) for water and − 12.7 mm (95% CI − 18.7 to − 6.7 mm) for saliva substitute. The proportion of patients who had improved dry mouth increased from 52% for water to 62% for saliva substitute. Conclusions: IM DRY successfully achieved its primary feasibility aims: recruitment rate, completeness of these, acceptability and protocol adherence. Saliva substitutes, used in the perioperative management of dry mouth, may be a simple, inexpensive, and low risk solution to help alleviate this common complaint. A large randomised controlled trial is feasible and is currently recruiting (ANZCTR 12619000132145).