A 10-month, hospital-based, open-label clinical study was undertaken of a unique antimicrobial nail solution containing surfactant, allantoin, and benzaikonium chloride to determine its effectiveness, in conjunction with periodic debridement, against pedal onychomycosis. Forty patients with microbial infection of the nails were enrolled in this study, in which a new, objective nail-scoring system was used. At the start of the study, the mean nail score was 8.3, and 79.8% of the nails scored had severe disease (on a scale of 0 to 10, with 10 defined as total nail involvement, accompanied by pain and thickening). By the conclusion of the study, the mean score had decreased to 2.5, 32.6% of the patients' nails were scored 0 or 1, and 90% of the patients subjectively judged their improvement as excellent or good.