The invention relates to a composition for the treatment of superficial lesions, in particular skin lesions, mucous membrane lesions and / or nail lesions, an applicator comprising such a composition and the use of such a composition. The composition comprises an effective amount of trichloroacetic acid, at least one thickener, and at a physiologically acceptable solvent. And is effective against a plethora of superficial lesions selected from the group consisting of viral warts, verrucae, water warts (molluscum contagiosum), corns and calluses, and skin hyperpigmentation: age spots, solar lentigo, senial lentigo, acne, keratosis pilaris, actinic keratosis, mouth ulcers (canker sores), cold sores, ingrown toenails, onychomycosis, eyelid xanthelasma.