Melanoma incidence was inversely associated with the total consumption of antibiotics (J01) in both sexes and protective (inhibitor) association was detected between broad-spectrum penicillin combined with a beta-lactamase inhibitor (J01CR), but not with broad-spectrum, beta-lactamase sensitive penicillin (J01CA), which raises the possible protective effect of beta-lactamase inhibitors, most likely clavulanic acid, on the development of melanoma. This evidence concerns the gene LACTB and melanoma.