The effects of 2-(10,11-dihydro-10-oxodibenzo [b,f]thiepin-2-yl)propionic acid (CN-100), which has a significant inhibitory effect on acute inflammatory reactions, on leucocyte emigration and proliferation of granulation were examined in this study. The compound obviously inhibited the protein exudation and polymorph emigration 6 h after application of carboxymethylcellulose pouch method. It also definitely inhibited the monocyte emigration occurring 24 h after carrageenin pleurisy, and the inhibitory activity of the compound was nearly equal to that of pranoprofen and weaker than that of indometacin. CN-100 inhibited the proliferation of granulation in the test by paper disk method, i.e., the compound inhibited wound healing. The antigranulation activity of CN-100 was also nearly equal to that of pranoprofen and weaker than that of indometacin. These results proved that CN-100 should definitely inhibit the reactions of the second and third inflammatory phases of the whole reactions from the exudative phase throughout proliferative phase, suggesting that the compound is a useful antiinflammatory drug.