The aim was to monitor the distribution of erythrosin-labelled saliva around the mouth during normal, unilateral chewing on gum. Thirty-one subjects chewed chewing-gum containing erythrosin on the preferred side for 5 min. The mouth was examined and the distribution of the dye recorded on standardized charts. The dye was present mainly ipsilateral to the chewing side. Although the dye did cross the mid-line, it was rarely present in the contralateral premolar and molar regions.