An 82 year-old woman with Parkinson's disease complained of a tendency to fall. She has had an extensive kyphosis since she was 66 years old. Over the last 6 months, she has repeatedly fallen. Even though she took anti-parkisonian drugs, she had also developed camptocormia. Her plasma levodopa concentration was analyzed for 4 hrs after administrating an oral dose of levodopa (200 mg) plus carbidopa (20 mg) at the time of fasting. The change in the plasma levodopa concentration showed bimodal peaks. The physical symptoms depended on the plasma concentration and improved twice. Esophageal tortuosity and esophageal hiatal hernia were detected by esophagography and upper gastric endoscopy. Such physical symptoms were speculated to have been caused by the transit disturbance of the drug in the gastrointestinal duct. During a second analysis of the plasma levodopa concentration, the patient was instructed to keep extending her back after consuming the same dose of drugs but with a greater amount of water than in the first analysis. A single and a higher peak were observed for the plasma levodopa concentration, and the physical symptoms, including camptocormia and parkinsonism, were improved. Hunched posture could influence the absorption of antiparkinsonian drugs.