The goal of this study is to evaluate the degree of staining and clinical efficacy of a chlorhexidine mouthwash with an antidiscoloration system (ADS) versus 0.2% chlorhexidine mouthwash (traditional). Secondary objectives are to evaluate the patient "compliance" factor according to patterns assigned by the clinician and to observe the side effects of the two mouthwashes. This comparative study is carried out on a sample of 15 non-smoking patients with chronic periodontitis at the Department of Periodontology, the International University of Catalunya, Barcelona, Spain. All patients used either 0.2% chlorhexidine mouthwash (control group = bottle B) or chlorhexidine with ADS (test group = bottle A) for 15 days. Each patient first rinsed with a randomly assigned mouthwash for 15 days followed by a 15-day washout period. Subsequently, each patient used a second mouthwash. Before each cycle, a full dental prophylaxis was performed. The plaque, gingival, and Brecx staining indexes were used. The results showed less tooth staining with the test group (P <0.01). No statistically significant differences were observed in plaque (P = 0.1496) and gingival indexes (P = 0.1688). Eighty-eight percent of patients followed the instructions outlined in the protocol. In terms of other adverse effects, two patients reported a bad taste with both mouthwashes. The test group with ADS had less staining than the control group during a usage period of 15 days. However, the two mouthwashes seemed to be equally effective as antiplaque and antigingivitis agents.