The aim of this study was to determine the impact of bethanechol administration concomitant to radiotherapy (RT) on oral mucositis, candidiasis and taste loss. We performed a secondary analysis of a previously conducted prospective randomized trial which evaluated the effect of bethanechol on salivary gland dysfunction before, during, and after RT for head and neck cancer (HNC), in comparison to artificial saliva. Mucositis, candidiasis and taste loss were analyzed in 36 patients. Mucositis was scored using the World Health Organization (WHO) method; candidiasis was diagnosed by means of clinical examination, whereas taste loss was assessed by the patients' subjective report of absence of taste. No significant differences were observed between groups in relation to frequency and severity of mucositis or frequency of candidiasis and taste loss. In conclusion, bethanechol does not appear to reduce the incidence of mucositis, candidiasis, and taste loss when administered during RT. (J Oral Sci 51, 565-572, 2009)