Haematein should not be confused with haematin, which is a brown to black iron-containing pigment formed by decomposition of haemoglobin.

Dissolved haematein slowly reacts with atmospheric oxygen, yielding products that have not found applications.

In acidic solutions, complexes of hematein with metals (usually aluminium or iron, but also chromium, zirconium and several others) are used as biological stains.

Metal-haematein stains are available also for objects other than nuclei, including myelin sheaths of nerve fibres and various cytoplasmic organelles.

As usually used, aluminium-hematein stains only nuclear chromatin and a few other materials such as keratohyalin granules and calcified deposits.