Efficacy of a Modified Banxia Xiexin Decoction for the "Wei-Pi" Syndrome (Postprandial Distress Syndrome)

Inclusion Criteria: * Permanent resident of Hong Kong with age from 18 to 60 * Have a diagnosis of Wei-Pi (postprandial distress syndrome, ie. at least one of bothersome postprandial fullness (ie, severe enough to impact on usual activities) and bothersome early satiation (ie, severe enough to prevent finishing a regular-size meal) at least three days per week for the last three months, with symptom onset at least six months before diagnosis Exclusion Criteria: * Pregnancy or pregnancy planners * Abnormal liver function (up to twofold the upper normal reference level of ALT)\[14\] or kidney function (estimated creatinine clearance \< 80 mL/min)\[15\] * History of diagnosed gastric structural abnormalities through endoscopy /History of gastric removal surgery * Have G6PD deficiency * Alcohol or drug abuser * Taking Chinese medicine within one month * Unable to read/understand and sign the informed consent document