Histotoxic hypoxia (also called
histoxic hypoxia) is the inability of cells to take up or utilize oxygen from the bloodstream, despite physiologically normal delivery of oxygen to such cells and tissues. Histotoxic hypoxia results from tissue poisoning, such as that caused by
cyanide (which acts by inhibiting
cytochrome oxidase), and certain other
poisons like
hydrogen sulfide (byproduct of sewage and used in leather tanning).