This study was designed to test the influence of pharmacological manipulation on scar contraction and craniofacial growth in rabbits after repairing surgically created lip defects by wide undermining of soft tissue. Two pharmacological agents, i.e. papaverine hydrochloride and hyaluronidase, were injected subcutaneously and submucosally in the wound. The preliminary results of this study indicated that the treatment with either papaverine or hyaluronidase for four weeks following lip repair with soft tissue undermining significantly reduced lip pressure and decreased tension of labial wound. Analysis of the data from the lateral head cephalography revealed that the rabbits treated with such pharmacological agents exhibited significantly more anteroposterior growth than the rabbits not treated with such agents.