Helicobacter is a class of bacteria commonly found in the gastrointestinal tracts of dogs, cats and people. It only becomes problematic when it causes clinical disease.Any breed, gender or age of cat can be infected by this microorganism. Unsanitary environmental conditions and overcrowding, as are present in some shelters and catteries, can predispose cats to develop clinical disease. However, most cats infected by Helicobacter never show signs of illness. In those cases where Helicobacter infection