The objective of this study is to evaluate the safety and feasibility of oral rehydration therapy for short hydration in patients with biliary tract cancer who will undergo the chemotherapy including gemcitabine and cisplatin.

A large amount of fluid infusion is required to load for the prevention of renal dysfunction by Cisplatin in combination of GC therapy. There is a problem infusion time is take a long time for this. In many institutions in Japan, GC therapy is performed over 3 hours or more, longer than original method in the ABC-002 trial. Oral rehydration therapy is a therapy that performs prevention or treatment of dehydration by the ingestion of oral rehydration solution, which is adjusted the concentration of the electrolyte and glucose to absorb good efficiency from the gastrointestinal tract. Oral rehydration therapy (ORT) is a therapy that performs prevention or treatment of dehydration by the ingestion of oral rehydration solution, which is adjusted the concentration of the electrolyte and glucose to absorb good efficiency from the gastrointestinal tract. Many reports suggest ORT may substitute for infusion therapy. Herein, the investigators planned the study to examine the safety of replacing the fluid infusion by oral rehydration expecting to shorten the time to drip.

Inclusion Criteria: 1. Patients with histological or cytological diagnosis of biliary tract cancer who haven't received cisplatin previously 2. Patients who is planned to receive chemotherapy including gemcitabine and cisplatin for biliary cancer for more than 12 weeks 3. Older than 20 years old 4. Eastern Cooperative Oncology Group Performance status of 0 or 1 5. Adequate main organ function 6. Fully oral intake ability to drink 500ml of solution before chemotherapy 7. Estimated life expectancy no less than 3 months 8. Written informed consent

- Exclusion Criteria: 1. Patients who received cisplatin previously 2. Radiological and clinical evidence of pulmonary fibrosis or interstitial pneumonia 3. Patients with uncontrolled diabetes mellitus or severe liver dysfunction or unstable angina or myocardial infarction within 3 months 4. Patients with serious infection 5. Pregnant or lactating female or patients who wish pregnant 6. Patients having severe allergy 7. Patients with other serious comorbid diseases 8. Patients with severe psychological disease 9. Patients with uncontrollable watery diarrhea 10. Patients with moderate or severe ascites /pleural effusion 11. Patients with severe psychological disease 12. Patients who are positive for a test of hepatitis B virus surface antigen (HBs antigen) without controlled with entecavir 13. Patients who is judged as an inappropriate case by the investigator

-