The aim of this study was to evaluate the efficacy and safety of recombinant human epidermal growth factor (rhEGF) oral spray for oral mucositis (OM) induced by intensive chemotherapy with hematopoietic stem cell transplantation. In this phase 2 study, patients were randomized to either rhEGF (50 microg/mL) or placebo in a 1:1 ratio. The primary endpoint was incidence of National Cancer Institute (NCI) grade ≥2 OM. A total of 138 patients were enrolled in this study. In the intention-to-treat analysis, rhEGF did not reduce the incidence of NCI grade ≥2 OM (p = 0.717) nor reduce its duration (p = 0.725). Secondary endpoints including the day of onset and duration of NCI grade ≥2 OM, the incidence of NCI grade ≥3 OM and its duration, and patient-reported quality of life were also similar between the two groups. In the per-protocol analysis, however, the duration of opioid analgesic use was shorter in the rhEGF group (p = 0.036), and recipients in the rhEGF group required a lower cumulative dose of opioid analgesics than those in the placebo group (p = 0.046), among patients with NCI grade ≥2 OM. Adverse events were mild and transient. This study found no evidence to suggest that rhEGF oral spray reduces the incidence of OM. However, further studies are needed to investigate the effect of rhEGF on OM-induced pain reduction after intensive chemotherapy.