Chlorhexidine (CLX) mouthrinse has been the gold standard as antiplaque solution.However, if its efficiency seems to be preserved even if the chlorhexidine concentration is bellow 0.10%, the formulation of the final product may affect the effectiveness. Thus, it can be concluded from this study that 0.12% CLX alcohol base mouthrinse is significantly more effective in inhibiting plaque than the diluted 0.1% CLX non-alcohol base containing formaldehyde mouthrinse.