Functional dyspepsia (FD) and irritable bowel syndrome (IBS) are frequent disorders affecting quality of life. They often require long-term treatment. Abdominal symptoms of both disorders can overlap, making differential diagnosis and treatment challenging. The extracts of the herbal combination preparation STW 5 (Iberogast®) exert pharmacological effects in different gastrointestinal regions and can address symptoms of both FD and IBS. This review summarizes safety and efficacy data of 12 clinical trials using STW 5 in FD and IBS since 1990. Double-blind and randomized studies versus placebo or active control found statistically significant effects of STW 5 on patients’ symptoms with a comparable efficacy to a standard prokinetic. Non-interventional and retrospective studies confirmed these effects. Various studies evaluated the tolerability profile of STW 5: the incidence of adverse drug reactions was 0.04 %. The worldwide spontaneous reporting system confirmed this profile. STW 5 has a favorable tolerability which is relevant for long-term treatment.