the substance has antimicrobial properties and was formerly used in various cosmetics (shampoos, soaps, skin creams, deodorants) This is no longer allowed according to the German Cosmetic Decree. Bithionol is also used in cooling lubricants. Bithionol can cause photoallergic reactions.
As a so-called persistent "light reactor", bithionol can induce skin changes in exposed skin areas after UV provocation in sensitized persons, even years after the previous contact(persistent light reaction or photocontact allergy).