The species Ageratina pichinchensis (Asteraceae) has been used for a long time in Mexican traditional medicine for the treatment of different skin conditions and injuries. In this study, the healing capacity of the plant extracts obtained was evaluated and, in order to understand the mechanism of healing, we also analyzed its effect on cell proliferation IN VITRO, cytotoxicity, and skin irritation. Different extracts obtained from the aerial parts of A. pichinchensis, topically administrated, were evaluated in a healing model by scalpel-blade incision on the rat. The extracts, at 10 % concentrations, were administrated daily during an eight-day period. A control group, to which the vehicle was administered, was used; while fibrinolysin (Fibrase SA®) was administered for positive control purposes. Reduction in wound size and the histological characteristics of the skin at the end of the treatment were evaluated. Cytotoxicity was evaluated in cell lines KB (nasopharyngeal carcinoma), UISO (squamous cell carcinoma of the cervix), OVCAR (ovarian carcinoma), and HCT-15 (colon carcinoma). In addition, the effect on cell proliferation of cell line MRC-5 (normal cells from human fetal lung) was measured, and skin irritation was evaluated. The results showed an important healing capacity of A. pichinchensis extract in noninfected wounds; the aqueous extract was found to be the most efficient. The extracts exhibited no cytotoxic effect; however, there was an effect that promoted cell proliferation in cell line MRC-5. The products tested demonstrated no skin irritant effects. © Georg Thieme Verlag KG Stuttgart · New York.