Ammonium bituminosulfonate

Ammonium bituminosulfonate or ammonium bituminosulphonate (synonyms of ichthammol, CAS#8029-68-3 brand name: Ichthyol) is a product of natural origin obtained in the first step by dry distillation of sulfur-rich oil shale (bituminous schists). By sulfonation of the resulting oil (or purified fractions thereof) and subsequent neutralization with ammonia Ichthammol results as viscous, water-soluble substance with characteristic bitumen-like odor. It is used in medicine as a remedy for treatment of different skin diseases, including eczema and psoriasis (see below). Ointments containing 10% or 20% Ichthammol are most common. They are sometimes called "black ointments" or "drawing salves". Ichthammol's dermatological action was promoted by German physician Paul Gerson Unna.