A double-blind clinical trial was performed to study the effect of epidermal growth factor (EGF) mouthwash on the healing and recurrence of oral ulceration in 12 patients undergoing cancer chemotherapy. The oral distribution or cytotoxic-induced ulcers corresponded to the salivary gutters. There was no difference in the rate of healing of established ulcers between the experimental and placebo groups. However, there was a small delay in the onset and severity of recurrent ulceration. It was concluded that EGF mouthwash does not accelerate ulcer healing, but it may have the potential to protect the oral epithelium from cytotoxic damage.