Our pilot results showed that meperidine reduce patient discomfort during EGD (esophagogastroduodenoscopy). But many patients can tolerate EGD well without any sedative agents. So the investigators target the use of meperidine on patients expected to have poor tolerance in this study, which includ young females with high anxiety level and patients with prior poor tolerance. The investigators test the hypothesis that meperidine improves tolerance and alleviates discomfort for patients expected to have poor tolerance during diagnostic EGD.

Inclusion Criteria:

• female youger than 65 years with high anxiety level
• patients with previous poor tolerance of EGD

Exclusion Criteria:

• a therapeutic EGD
• sedation with other agents
• contraindication to Buscopan (hyoscine N-butylbromide) or meperidine
• American Society of Anesthesiology (ASA) risk Class 3 or higher, renal failure
• age less than 20 years or more than 80 years
• pregnancy
• refusal to provide written informed consent. All participants signed written informed consents