Various forms of vasculitis may result in mesenteric ischaemia, ischaemic colitis or aneurysm formation in the aorta or intestinal blood vessels. Vasculitides may involve large- and/or medium-sized vessels, medium- and/or small-sized vessels, or small-sized vessels only. It is essential to differentiate between the different forms of vasculitis since diagnostic tests and therapies differ greatly. Gastrointestinal manifestations of vasculitis can generally be detected using angiography, digital subtraction angiography and/or magnetic resonance angiography (MRA). Various laboratory tests are helpful in establishing the diagnosis in patients in whom vasculitis is clinically suspected. In addition, the diagnosis should be confirmed using histology or angiography if possible. Treatment of vasculitis not caused by chronic infection consists of high dose corticosteroids and, in the case of polyarteritis nodosa or vasculitis associated with anti-neutrophil cytoplasmic antibodies (ANCA), cyclophosphamide.