TubastatinA is a potent, selective HDAC6 inhibitor with an IC50 of 15nM in cell-free tests, which is far more selective than all other isoenzymes (1000 times) except HDAC8(57 times). TubastatinA promotes autophagy and increases apoptosis. TubastatinA reduces the growth of bile duct cancer in the body. TubastatinA(10mg/kg) treated with the isogenic rat model of in-situ cholangiocarcinoma induced 6 times less than the average tumor weight and reduced the ratio of tumor weight to liver weight and body weight (5 and 5.6 times, respectively). TubastatinA treated the tumors and significantly reduced the number of PCNA positive cells compared to the control group (34%vs65%). TubastatA, administered intraperitoneally at a dose of 30mg/kg, significantly inhibited paw volume in animal models of Fredrin complete adjuvant (FCA) -induced inflammation. TubastatA(30mg/kg intrabitoneal injection) treated paw tissue of mice with collagen-induced arthritis DBA1 significantly reduced clinical scores (~ 70%) and IL-6 expression.