Thromboxane is a member of the family of lipids known as eicosanoids. It is produced in platelets by thromboxane synthetase, which is produced from the endoperoxides by the cyclooxygenase (COX) enzyme from arachidonic acid.

Enzymes and substrates associated with thromoboxane and prostacyclin synthesis.

Thromboxane is a vasoconstrictor and facilitates the clumping of platelets. It is in homeostatic balance in the circulatory system with prostacyclin, a related compound. The widely-used drug aspirin acts by inhibiting the ability of the COX enzyme to synthesize the precursors of thromboxane within platelets.

Thromboxane is named for its role in clot formation (thrombosis).