Whether tranilast had antagonistic effect on proliferation inhibition and collagen synthesis promotion induced by TGF-β2 in cultured human trabecular meshwork cells was investigated. Suspension of 1 × 104 cultured human trabecular meshwork cells of 3-5 passage was distributed in each well of a 96-well disk and divided into control group and experimental group. After 24 h, 0 μg/ml (control), 12.5 μg/ml, 25 μg/ml, 50 μg/ml tranilast with 3.2 ng/ml TGF-β2 were added into the incubation medium. Another 24 h later, proliferation and collagen synthesis in cultured human trabecular meshwork cells were examined respectively by using tetrazolium-based semiautomated colormetric (MTT) assay and 3 H-proline incorporation with liquid scintillation technique. The results showed absorbance (A) values of the experimental groups were 0. 9036 ± 0. 3017, 1.1361 ±0.1352, 1.2457 ±0.1524 according to the different concentrations of tranilast, and 0. 8956 ±0. 1903 of the control group. In comparison with the control group, 25 μg/ml (q′= 3. 23, P＜0.05), 50 μg/ml (q=4.70, P＜0.01) tranilast significantly antagonized the decrease of the A values induced by TGF-β2 in the cultured human trabecular meshwork cells. In comparison with the control group [817.37±124.21 cpm/104 cells], 12.5 μg/ml (620.33±80.46 cpm/104 cells, q′=4.26, P＜0.05),25 μg/ml (594. 58±88.13 cpm/104 cells, q′=4. 81, P＜0.01), 50 μg/ml (418. 64±67.90 cpm/104 cells, q′=8.62, P＜0.01) tranilast significantly inhibited the incorporation of 3 H-proline into the cultured human trabecular meshwork cells promoted by TGF-β2 in a dose-dependent manner. It was concluded that tranilast had the antagonistic effect on the proliferation inhibition and collagen synthesis promotion induced by TGF-β2 in the cultured human trabecular meshwork cells.