Flavonoids are natural polyphenolic compounds present in a wide spectrum of plants that have a beneficial effect on human health. In the context of cardiovascular diseases related to plaque and thrombus formation, flavonoids exhibit an anti-aggregatory effect. Previously, it has been reported that all tested flavonoids exhibit an antiaggregatory effect on platelet aggregation when measured by impedance aggregometry on whole blood, in the test of aggregation induced by adenosine diphosphate (ADP). As not all flavonoids have the same targets within signaling pathways, an assumption of a common non-specific mechanism related to lipophilicity is to be considered. To test this hypothesis, reverse-phase thin layer chromatography was used to assess the lipophilicity of flavonoids; impedance aggregometry was used for testing of platelet aggregation and flow cytometry to monitor the influence of flavonoids on platelet activation. Lipophilicity analysis showed a highly negative correlation of log