Persimmon condensed tannins (PT) are highly polymerized (mDP = 26) and highly galloylated (72%) proanthocyanidins. Its pleiotropic effects in oxidation resistance, neuroprotection, hypolipidemia, and cardio-protection both in vitro and in vivo were widely reported. Because large proanthocyanidins are unlikely to be absorbed in the gastrointestinal tract, it is believed that the interaction of PT with biological membranes may play a crucial role in its biological activities. In the present study, the capacities of PT adsorbing to membrane, partitioning into membrane, and its influence on the membrane fluidity were investigated by fluorescence quenching, isothermal titration calorimetry (ITC) and fluorescence anisotropy measurements in a biomembrane-mimetic system composed of 1-palmitoyl-2-oleoylphosphatidylcholine (POPC), 1-palmitoyl-2-oleoylphosphatidylethanolamine (POPE), sphingomyelin (SPM), and