The permeation and cytotoxicity of three insu-lin-mimetic vanadium(III, IV, V)-dipicolinate complexes were studied using the MDCK cell monolayer in comparison with the Caco-2 cells. On MDCK cell monolayer, the appar-ent permeation coefficients (Papp) were estimated to be (7.5 ± 1.0)×10?6, (1.0 ± 0.2)×10?6, (1.7±0.4)×10?6 cm/s for V(V), V(IV), and V(III)-dipic complexes, respectively. The perme-ability of V(V)-dipic complexes is much better than the oth-ers, which is in agreement with its better hypoglycemic effect in animal tests. On Caco-2 cell monolayer, Papp were found to be in the range of 1-3×10?6 cm/s and not to be affected by excessive amounts of dipicolinate ligand. By contrast, the permeability in the AP→BL direction across the MDCK monolayer increased greatly in the presence of free ligands, suggesting existence of active transport mechanism of vana-dium complex anions on the MDCK cells. The cytotoxicity of the three complexes was found similar and the IC50 were measured in the range of 0.6―0.9 mmol/L for MDCK cells and 1.6―2 mmol/L for Caco-2 cells. The cytotoxicity of three vanadium complexes was conceivably in consistence with their permeability, suggesting that the toxicity, permeation and cellular metabolism of vanadium complexes are closely related. The permeation and cytotoxicity of three insu-lin-mimetic vanadium (III, IV, V) -dipicolinate complexes were studied using the MDCK cell monolayer in comparison with the Caco-2 cells. On MDCK cell monolayer, the appar-ent permeation coefficients Papp were estimated to be 7.5 ± 1.0 × 10 6, 1.0 ± 0.2 × 10 6, 1.7 ± 0.4 × 10 -6 cm / s for V (V), V The perme-ability of V (V) -dipic complexes is much better than the oth-ers, which is in agreement with its better hypoglycemic effect in animal tests. On Caco-2 cell monolayer By contrast, the permeability in the AP → BL direction across the MDCK monolayer increased greatly in the presence of free ligands, suggesting existence of active transport mechanism of vana-dium complex anions on the MDCK cells. The cytotoxicity of the three complexes was found similar similar to the IC50 were measurable ured in the range of 0.6-0.9 mmol / L for MDCK cells and 1.6-2 mmol / L for Caco-2 cells. The cytotoxicity of three vanadium complexes was conceivably in consistence with their permeability, suggesting that the toxicity, permeation and cellular metabolism of vanadium complexes are closely related.