The global incidence and prevalence of eosinophilic gastrointestinal diseases is rising. Clinically, acute eosinophilic esophagitis cannot be distinguished from other causes of esophagitis. Endoscopic findings like rings, webs or furrows have a lower sensitivity than previously assumed. An improvement of symptoms by proton-pump inhibitors also doesn't rule out the diagnosis - it has to be confirmed histologically. Early therapy will prevent later complications like strictures and motility disorders. The presentation of eosinophilic gastroenteritris/colitis is even less specific. Common cause seems to be a Th2-mediated food allergy. Successful therapies include allergen-free diets and topic steroids. Additionally, in the case of proton-pump inhibitor-responsive eosinophilic esophagitis, proton pump inhibitors do not only block gastral acid production, but may also have a direct inhibitory effect on Th2-immunity. Therefore, Th2-specific biologicals have theoretical advantages, but they could not really convince in first clinical studies.