A fungal nail treatment composition comprises a proton source in the form of an organic acid, preferably citric acid or acetic acid (5-15% w/w). The composition most preferably further comprises a humectant, preferably glycerin or polypropylene glycol (15-40% w/w)； a film forming agent, preferably xanthan gum (0.1-1% w/w)； a penetration enhancing agent, preferably thioglycolic acid, sodium thioglycolate, potassium thioglycolate, urea or other keratolytic agents (1-5% w/w)； and a solvent, typically water. Additional components may be selected from a nail conditioner (preferably panthenol), additional solvents (preferably isopropyl alcohol, ethanol or acetone), a preservative (preferably sodium benzoate, sodium sorbate, sorbic acid or benzoic acid) and a UV inhibitor. Exemplified compositions consist of citric acid monohydrate (12% w/w), glycerine (20% w/w), xanthan gum (0.3% w/w), isopropyl alcohol (20% w/w), panthenol (1.0% w/w), sodium benzoate (0.2% w/w), a UV inhibitor (0.05% w/w) and optionally thioglycolic acid (1-5% w/w). These compositions are useful in the treatment of fungal nail infection (onychomychosis) of the toenails or fingernails caused by dermatophytes, in particular Trichophyton rubrum. A fungal nail treatment device comprising the composition of the invention is also claimed.
