Ankaferd Blood Stopper(R) (ABS), a standardized mixture of five plants, has been used historically as a haemostatic agent but its mechanism of action remains unknown. This study investigated the in vitro effects of ABS on haemostatic parameters. When added to plasma or serum, ABS induced the very rapid formation of a protein network and erythrocyte aggregation. The levels of coagulation factors II, V, VII, VIII, IX, X, XI, and XIII were not affected by ABS. Plasma fibrinogen activity and antigen levels were decreased following the addition of ABS, in parallel with the prolonged thrombin time. Total protein, albumin, and globulin levels decreased after the addition of ABS. Our findings suggest that ABS stimulates the formation of an encapsulated protein network that provides focal points for erythrocyte aggregation. ABS has the therapeutic potential to be used for the management of haemorrhage and this agent should be investigated further in clinical trials.