Purpose: One of the most common complications of hyperbaric oxygen (HBO2) therapy is middle ear barotrauma (MEB), occasionally causing otalgia. The objective of this study was to evaluate the effect of dried salted plum consumption on MEB and otalgia associated with HBO2 therapy. Materials and methods: Patients undergoing the first chamber session of HBO2 therapy were included in the present prospective randomized controlled trial. The Valsalva maneuver was administered to all patients before HBO2. The patients were randomly divided into two groups: One that ate a dried salted plum during HBO2 treatment and the other that did not. An otoscopic examination was performed after HBO2 therapy. The MEB was graded according to Teed scores. The degree of otalgia was recorded using the Visual Analog Scale (VAS). Results: Ninety patients were enrolled. The overall incidence of MEB (Teed score grade 1∼4) was 39.6% (21 of 53) for patients administered a dried salted plum versus 37.8% (14 of 37) for the control group (P=1.000). The incidence of mild MEB (Teed score grade 1∼2) and severe MEB (Teed score Grade 3∼4) between the two groups was not significantly different. Otalgia was present in 5.7% (3 of 53) of patients administered a dried salted plum versus 18.9% (7 of 37) for the control group (P=.085). No patients administered a dried salted plum had a VAS score ≥4 for otalgia versus 10.8% (4 of 37) for the control group (P=.026). Conclusions: Dried salted plum consumption does not decrease the incidence of MEB, but may ameliorate the severity of first chamber session HBO2-induced otalgia.