Treatment of Shugan Hewei recipe in the treatment of gastroesophageal reflux disease (GERD)

INTERVENTION: Participants will be randomized to receive either: 1. Shugan Hewei recipe herbal granules and matching Omeprazole placebo tablet for 4 weeks or 2. Omeprazole tablet and matching Shugan Hewei recipe herbal placebo granules for 4 weeks. Herbal granules were dissolved in 300 ml of boiled water, 150 ml twice daily. Omeprazole tablet 20 mg once a day, on an empty stomach. CONDITION: Gastroesophageal reflux disease (GERD) ; Digestive System PRIMARY OUTCOME: GERD questionnaire score, measured at baseline, 2 weeks and 4 weeks SECONDARY OUTCOME: 1. Traditional Chinese Medicine syndromes of IBS score, measured at baseline, 2 weeks and 4 weeks; 2. High resolution manometry (HRM), measured at baseline and 4 weeks INCLUSION CRITERIA: 1. Patients with GERD, GERD questionnaire score >8 2. Patients able to give informed consent 3. Female patients of childbearing potential who are willing to use at least one highly effective contraceptive method 4. Aged 18‐65 years, either sex