Background Mitochondrial diseases are an important group of inherited neurometabolic disorders that invariably exhibit multi-organ involvement, are relentlessly progressive, and result in significant morbidity and mortality. They may manifest as discrete clinical syndromes such as mitochondrial encephalomyopathy, lactic acidosis, and stroke like episodes (MELAS), chronic and progressive external ophthalmoplegia (CPEO), and maternally inherited deafness and diabetes (MIDD), or more commonly with a wide overlapping spectrum of clinical features, including hypertrophic cardiomyopathy and gastrointestinal (GI) dysmotility. Symptoms arising from gastrointestinal (GI) dysmotility in patients with mitochondrial disease are increasingly recognized and often include dysphagia, abdominal pain, abdominal distention, bacterial overgrowth, constipation, and in severe cases, intestinal pseudo obstruction mimicking an acute surgical abdomen. The high incidence of this was recently confirmed when we surveyed 86 mitochondrial patients about GI symptoms. Sixty five percent of patients experienced GI dysmotility symptoms, including constipation, early satiety, abdominal pain and abdominal distension (under preparation for publication). Although the proposed pathological mechanisms underlying the development of GI dysmotility remain diverse, potential mechanisms include mitochondrial dysfunction of smooth muscle within the GI tract and visceral myopathy. Moreover, bacteria within the GI tract, termed 'gut microbiota' has also been identified as a key contributor towards GI dysmotility.