Histiocytic ulcerative colitis is an uncommon cause of canine large bowel diarrhoea that is generally refractory to standard treatment for idiopathic colitis. It is characterised pathologically by mucosal ulceration with a mixed inflammatory cell infiltrate, in which periodic acid‐Schiff positive histiocytes are a dominant feature. The disease is well recognised in young boxer dogs in the USA, Australasia and mainland Europe. This paper reports the occurrence of seven cases of histiocytic ulcerative colitis seen recently in the UK, along with the clinical signs, histopathology, treatment and post mortem findings.