Vasculitis, defined as a non-infectious inflammatory disorder of blood vessels, can affect vessels of any type in any organ. The gastrointestinal (GI) tract may thus also be involved. In systemic disorders as mixed connective tissue disease (MCTD) and systemic lupus erythematodes (SLE), patients may present with symptoms of gastrointestinal disfunction such as motility disorders, caused by alterations in the connective tissue. True vasculitis however also occurs in the GI tract. Severe, occlusive damage often leads to ischemia that may result in ulceration and perforation. Non-occlusive vascular disease may lead to vascular leakage resulting in oedema and haemorrhage. Those patients often present with diarrhoea or symptoms of bleeding. GI involvement is frequent in Henoch-Schönlein purpura and also often noted in polyarteritis nodosa (PAN), microscopic polyangiitis, Wegener's syndrome and Churg-Strauss syndrome. Furthermore, GI vasculitis has also been described in giant cell arteritis, Takayasu's disease, Buerger's disease and leucocytoclastic vasculitides as essential mixed cryoglubulinemia, lupus vasculitis, rheumatoid disease, MCTD, drug-induced vasculitis and Behçet's disease. The diagnosis and classification of vasculitis relies upon a combination of clinical, serological, haematological, radiological and histological findings. Establishing a precise diagnosis can be difficult but is important because treatment and prognosis can be highly variable.