Two types of mucoadhesive semi-solid formulations (hydrophilic and hydrophobic) for the treatment of mucositises, stomatitises and aphtae were investigated in healthy human volunteers using a gamma scintigraphic technique. The investigations showed that the clearance of hydrophobic formulations follows zero order kinetics whereas the hydrophilic formulation follows a biphasic elimination pattern. All formulations showed an acceptable tolerance but the subjects' preference went clearly to the hydrophobic formulations. Hydrophobic formulations maintained their adhesive and cohesive properties throughout the test period, loosing less than 10% activity within the first hour, whereas about 50% of the mucoadhesive hydrophilic preparation was eliminated within the same time period.