Dyspepsia has been defined as every unpleasant sensation in epigastrium associated with gastroduodenal disorders. According to Rome IV, functional dyspepsia (FD) is diagnosed with presence of one or more of four symptoms (i.e. postprandial fullness, early satiation, epigastric pain, epigastric burning) in the absence of organic or metabolic causes. FD is also divide into two subgroups; postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS) that usually overlap. The prevalence rate of FD is estimated up to 40% of general population. FD caused by several factors such as impaired gastric accommodation, hypersensitivity to gastric distention, altered duodenal sensitivity to lipid or acid, abnormal intestinal motility, and central nervous system (CNS) dysfunction. Several studies have reported effectiveness of herbal medicine on FD. This article, thus, reviews Persian herbal medicine in FD.

Electronic databases including Pubmed, Scopus, Cochrain, Embase, Science direct, Web of science and SID were searched so as to find clinical articles related to Functional dyspepsia and herbal medicine since 2019. Our keywords were traditional medicine, complementary and alternative medicine (CAM), herb, plant, and dyspepsia. Non-randomized clinical trial, non-relevant studies, supplement, vitamins, pre or probiotics and non-persian herbal drugs were excluded.

We found 14 randomized clinical trials with 14 Persian herbal medicine, affecting patients with FD. According to the results, several herbs like Asparagus racemosus, Ocimum basilicum, Mentha longifolia, Mentha pulegium, Pimpinella anisum, Nigella sativa, Mentha spicata and Zingiber officinale can improve the symptoms of patients with PDS. Also Mastic gum, Curcuma longa, Pistatio atlantica, Glycyrrhiza glabra and remedies of Rosa damascene & Crocus sativus and Trachyspermum copticom & Apium graveolence are effective in both EPS and PDS.

There are several studies which have focused on the mechanism of herbal effects in gastrointestinal (GI) system. It seems herbal medicine can modulate GI motility and secretions. nevertheless, more studies are needed to prove them.