The main aim of this study is to establish whether Mastiha products ameliorate functional dyspepsia symptoms.

Functional dyspepsia has an approximate prevalence of 20% and is one of the main causes of upper abdominal discomfort. Its pathogenesis remain unclear and therapeutic options remain limited with patients seeking alternative therapies in herbal remedies. Mastiha has been proven to significantly improve symptoms in patients with functional dyspepsia compared to placebo. In the present study, the investigators aim to determine whether Mastiha capsules or Mastiha water have a better effect on the improvement of functional dyspepsia symptoms. Therefore, the investigators designed a randomized, three-way cross-over clinical trial. Fifty patients with functional dyspepsia, will be randomized over three treatment sequences of 30 days each, separated by 14-day washout periods. The three treatments will be: Mastiha capsules, Mastiha water or Mastiha free treatment. The primary outcome, which will be assessed by intention to treat, will be the Leuven Postprandial Distress Scale, a validated instrument for the assessment of symptoms in functional dyspepsia, supported by the European Medicines Agency.

Inclusion Criteria:

functional dyspepsia diagnosis according to

• Rome criteria
• negative urea breath test for Helicobacter pylori
• upper gastrointestinal tract endoscopy with biopsy

Exclusion Criteria:

• organic diseases, such as peptic ulcer, gastrointestinal neoplasms, gastroesophageal reflux, irritable bowel syndrome
• pregnancy or lactation
• history of abdominal surgery or actinotherapy
• mental illness
• Severe impairment of heart, liver, or kidney function or respiratory function
• Alcohol overuse