D-penicillamine therapy is considered an effective and safe treatment for Wilson’s disease. Except for one experimental study, there has been no re- port in the literature about the development of disseminated intravascular coagulation (DIC) with the use of the drug. A 24-year-old female patient with Wilson’s disease, followed up with zinc and D-penicillamine treat- ment, was admitted to the emergency service because of oral mucosal bleeding and lethargy. Initial laboratory tests showed hemoglobin 7.1 g/dL (11.7-15.5), platelet 24×103 μL-1 (159-388), total bilirubin 18 mg/dL (0.3- 1.2), direct bilirubin 9.8 mg/dL (0-0.2), INR >10 (0.8-1.2), aPTT 64.5 s (22.5-32), fibrinogen 23 mg/dL (180-350), and factor 8 26.4% (70-150). Melena, hematemesis, and hematochezia were not present, and no active bleeding focus was detected on endoscopic evaluation. Upon meeting the DIC criteria, the patient underwent plasma exchange four times for the treat- ment of acute-on-chronic liver failure. Haemocomplettan-P, cryoprecipitate replacements were made as a supportive treatment for DIC. As the clini- cal bleeding continued despite plasma exchanges and factor replacement treatment, D-penicillamine was switched to trientine (1250 mg/day). After this change, the mucosal bleeding stopped, and DIC parameters improved. We suggest that if hemorrhagic complications develop on D-penicillamine treatment, the possibility of DIC induced by D-penicillamine activating the fibrinolysis should also be considered.