Rumination syndrome is a functional disorder characterized by the involuntary regurgitation of recently swallowed food from the stomach into the mouth, from where it can be re-chewed or expelled. Clinically, it is characterized by repeated episodes of effortless food regurgitation. The most usual complaint is frequent vomiting. The physical mechanism that generates regurgitation events is dependent on an involuntary process that alters abdominal and thoracic pressures accompanied by a permissive oesophageal-gastric junction. The diagnosis of rumination syndrome is clinical, highlighting the importance of performing an exhaustive anamnesis on the characteristics of the symptoms. Complementary tests are used to corroborate the diagnosis or rule out organic pathology. Treatment is focused on behavioural therapies as the first line, reserving pharmacological and surgical therapies for refractory cases.