It is well known that gingivitis is a bacterially-elicited inflammation of the marginal gingiva. A number of chemical agents have been evaluated over the years with regard to their antimicrobial effects in the oral cavity; however, all are associated with side effects that prohibit regular long-term use. Therefore, the effectiveness of a natural Mexican Sanguinaria extract (Polygonum aviculare L.) against gingivitis, was assessed in 60 male dentistry students between the ages of 18 and 25 years. Over a period of 2 weeks, these students used the Sanguinaria extract (1 mg/ml) in oral rinse twice daily as a unique oral health measurement (no tooth-brushing was allowed). The O'Leary Plaque Index and the Löe and Silness Gingivitis Index were recorded at baseline (day 0) in all the subjects. Also, a complete prophylaxis was performed after both indices were obtained. The antibacterial and antiinflammatory effects of the extract were evaluated on days 7, 11 and 14. The results showed that the Mexican Sanguinaria extract in oral rinse significantly decreased gingivitis from day 0 (-x=1. 056) to day 14 (-x=1.011) (P</=0.05). In contrast, a significant increase in dental plaque was observed from day 0 (-x=91.38) to day 14 (-x=98.69) (P</=0.05); however, the consistency of this plaque permitted its mechanical flushing easily. From this study, it is concluded that the Mexican Sanguinaria extract in oral rinse can be employed supportively in the therapy of gingivitis.