Inclusion Criteria:  have a clinical diagnosis of mild to moderate DSO in the nail of at least one great toe, with 20% to 50% clinical involvement of the target toenail, without dermatophytomas or lunula (matrix) involvement, without lunular or proximal involvement. exhibit positive mycology results (i.e., KOH test and culture of a dermatophyte) from the target great toenail, confirming common dermatophytes such as T. rubrum. are willing to refrain from using polish or other medication on treated toenails or on the skin immediately adjacent to the toenails during the treatment period unless directed to do so by the investigator. are willing to refrain from using topical steroids or topical antifungals on toenails or the skin immediately adjacent to the toenails or systemic antifungals for the duration of the study. are willing to provide signed and dated written voluntary informed consent in English before any protocol-specific procedures are performed. are able to complete the study and comply with study instructions.  Exclusion Criteria:  females who are pregnant, plan to become pregnant during the study, or are nursing a child. persons who are hypersensitive to topical creams, ointments, medications, or surfactants. persons who have received systemic antifungal therapy for any reason within 3 months, or topical antifungal therapy on the toenails or skin immediately adjacent to the toenails within 3 weeks prior to the start of the study. persons who have received an investigational drug within 4 weeks of the first dose of study product, or who are scheduled to receive an investigational drug other than the study product during the study. persons who have participated in a clinical trial for the systemic treatment of onychomycosis of the toenails within 6 months prior to the first dose of study product. persons who are not prepared to give up use of any nail cosmetic products for the duration of the study. persons who have any known immunodeficiency or history of malignancy in the last 4 years, excluding nonmelanoma skin cancer. persons currently suffering from any disease or condition, that could include abnormal laboratory tests, and/or who are currently using medication which in the opinion of the investigator may affect the evaluation of the study product or place the subject at undue risk. persons with psoriasis, lichen planus, or other medical conditions known to induce nail changes, other abnormalities or can causes of nail breakdown that can predispose to secondary fungal infection. Trauma from ill-fitting shoes, running, or overly aggressive nail care can also induce changes visually indistinguishable from onychomycosis that could result in a clinically abnormal toenail. patients with glucose-6 phosphate dehydrogenase (G6PD) deficiency or hypersensitivity/allergies to methylene blue persons with a history of any condition that could possibly affect absorption of drug (e.g., gastrectomy), uncontrolled diabetes, clinically significant peripheral vascular disease or peripheral circulatory impairment, or has had any major illness within 30 days prior to the screening examination. persons with a history of drug, prescription medicine, or alcohol abuse within the past 2 years. smokers.