the decrease of facial movements in peripheral facial paralysis and the resulting aesthetical sequels may have important emotional repercussions as a consequence to the functional deficit, and depending on the intensity of the clinical condition. Orofacial rehabilitation has as a purpose to favor the recovery of orofacial movements and to adequate and/or adapt orofacial functions and facial mimic. However, quantifying therapeutic results in an attempt to measure the muscle tonus is a challenge. Generally, the used forms of measurement are general and subjective. to propose the labial commissure angle as an anthropometric marker and to evaluate its reliability as an objective tool to evaluate the modification of the facial muscle tonus after rehabilitation. participants of the study were 20 patients presenting peripheral facial paralysis - level IV. The study was conducted using images from the photographical documentation taken fifteen days to one year post-onset of facial paralysis. The angle was measured by tracings determined by pre-established anthropometric facial points, such as the line between the glabella and the gnation and the crossing with the left and right chelion points determining an angle manually measured with a protractor on the photography. The average Labial Commissure Angle before treatment was of 101.70 and after rehabilitation of 93.80 (standard deviation, SD = 4.3). The statistical analysis indicated a significant difference (p < 0.001). the results obtained suggest that the Labial Commissure Angle allows the objective evaluation of facial muscle tonus modification.22119-24