Background - Calendula officinalis is commonly called the marigold. It is a staple topical remedy in homeopathic medicine. It is rich in quercetin, carotenoids, lutein, lycopene, rutin, ubiquinone, xanthophylls, and other anti-oxidants. It has anti-inflammatory properties. Quercetin, one of the active components in Calendula, has been shown to inhibit recombinant human matrix metalloproteinase (MMP) activity and decrease the expression of tumor necrosis factor-α, interleukin-1β (IL), IL-6 and IL-8 in phorbol 12-myristate 13-acetate and calcium ionophore-stimulated human mast cells.Objectives - To examine the effects of Calendula on human gingival fibroblast (HGF) mediated collagen degradation and MMP activity.Material and methods - Lactate dehydrogenate assays were performed to determine the non-toxic concentrations of Calendula, doxycycline and quercetin. Cell-mediated collagen degradation assays were performed to examine the inhibitory effect on cell-mediated collagen degradation. Gelatin zymography was performed to examine their effects on MMP-2 activity. The experiments were repeated three times and ANOVA used for statistical analyses.Results - Calendula at 2–3% completely inhibited the MMP-2 activity in the zymograms. Doxycycline inhibited HGF-mediated collagen degradation at 0.005, 0.01, 0.02 and 0.05%, and MMP-2 activity completely at 0.05%. Quercetin inhibited HGF-mediated collagen degradation at 0.005, 0.01 and 0.02%, and MMP-2 activity in a dose-dependent manner. Calendula inhibited HGF-mediated collagen degradation and MMP-2 activity more than the same correlated concentration of pure quercetin.Conclusion - Calendula inhibits HGF-mediated collagen degradation and MMP-2 activity more than the corresponding concentration of quercetin. This may be attributed to additional components in Calendula other than quercetin.