Ichthammol or ammonium bituminosulfonate (brand name Ichthyol), also known as black ointment, is a medication derived from sulfur-rich oil shale (bituminous schists).

It is used (sometimes in combination with zinc oxide) as a treatment for different skin diseases, including eczema and psoriasis (see below).

Ichthammol is obtained through three steps from bituminous schists: dry distillation, sulfonation of the resulting oil (or purified fractions thereof), and finally neutralization with ammonia.

An "ammonium sufobitol" (Tumenol-Ammonium), made from light shale oil of the Messel pit, was sold until 2000 in Germany.

[9] The Chinese material labelled as "ichthammol" are actually an ersatz product made from vegetable oil.

Ichtasol (USAN: Ictasol) is produced from the light (as opposed to heavy) fraction of distilled shale oil.

[6][14][15] According to the "list of preferred Specials" by the British Association of Dermatologists (BAD) ichthammol can be used in dermatology prescribing to treat acutely inflamed atopic eczema, among others.

The Committee for Medicinal Products for Veterinary Use (CVMP) decided that due to good tolerance and safety, there is no need to establish an MRL for ichthyol-substances.