Cilj ovog istraživanja je prikazati učinke i razlike u toksičnosti te prooksidativne i antihemostatske mehanizme triju biljnih formulacija namijenjenih ljudskoj uporabi kao dodaci prehrani, a koja sadrže pripravak biljke Ginkgo biloba, dostupne na području Republike Hrvatske. Istražen je i njihov učinak u kombinaciji s antihemostatskim lijekovima, acetilsalicilnom kiselinom i varfarinom. Istraživanje je provedeno na životinjskom modelu štakora. Testovima agregacije i koagulacije dokazano je da svi korišteni biljni pripravci produžuju vrijeme agregacije trombocita dok na koagulaciju nemaju statistički značajan učinak. Dokazano je da korištenje biljnih pripravaka u kombinaciji s lijekovima mijenja vrijednosti mjerenih biljega oksidativnog stresa, aktivnost enzima superoksid dismutaze (SOD) i katalaze te koncentraciju reduciranog glutationa (GSH) i malondialdehida (MDA) u tkivu jetre, bubrega, slezene i mozga, te u krvi. Dobiveni rezultati ukazuju na potrebu veće pozornosti prilikom upotrebe pripravka ginka i različitih antihemostatskih lijekova u svakodnevnoj kliničkoj praksi. The aim of this study was to demonstrate the effects and the differences in toxicity and prooxidant and antihemostatic mechanisms of three herbal dietary supplements, containing extract of Ginkgo biloba, that are available in Croatia. The goal was also to investigate their efect in combination with antihemostatic drugs, acetylsalicylic acid and warfarin. The study was conducted on animal model. Platelet aggregation and coagulation tests proved that all used herbal products prolong platelet aggregation, while on coagulation they had no statistically significant effect. It has been shown that the use of herbal dietary supplements in combination with medicaments changes the value of the measured biomarkers of oxidative stress, the activity of superoxide dismutase (SOD) and catalase and concentration of glutathione (GSH) and malondialdehyde (MDA) in tissues of liver, kidney, spleen and brain, and also in blood. The results suggested that the greater attention should be paid to the usage of these products in clinical practice.