Acquired coagulation factor X activity deficiency connected with Hymenoxys odorata DC (Compositae), bitterweed poisoning in sheep.

An acquired coagulation factor X activity deficiency was demonstrated in sheep fed Hymenoxys odorata, bitterweed plant. All coagulation tests were normal before the sheep were given the plant material. All tests involving the function of factor X, including a specific factor assay, became abnormal after the sheep were given bitterweed. Other specific factors remained within normal limits. The presence of an inhibitory activity could not be shown.