A 49-year-old man, who had a 30-year history of drinking the equivalent of 80 g of ethanol per day, underwent a detailed medical examination for cough and dyspnea. Chest-abdominal computed tomography and endoscopic retrograde pancreatography led to the diagnosis of a mediastinal pancreatic pseudocyst resulting from obstruction of the pancreatic duct by a protein plug. The pseudocyst rapidly improved with conservative treatment with camostat mesilate, H2-receptor antagonist and digestive enzymes. Although the patient abstained from alcohol for approximately 6 months, he resumed drinking, leading to recurrent attacks of pancreatitis. Bromhexine hydrochloride was then administered for 6 months, with the expectation that it would have a mucolytic effect on the pancreatic juice, resulting in improvement in the clinical symptoms, pancreatic enzymes and pancreatic exocrine function, as well as elimination of the protein plug. Bromhexine hydrochloride may be a new therapy for pathological states, such as alcoholic chronic pancreatitis, in which there is increased viscosity of the pancreatic juice because of elevated protein concentration, leading to protein plug formation and temporary blockage of the pancreatic duct.