The big brown eyes and beautiful temperament has made this breed increasingly popular in recent years, which has created problems. Over breeding has lead to an increase in the heart condition Mitral Valve Disease in the breed, often resulting in premature death. It is vital to check the medical history several generations back of potential parents before choosing a pup or breeding yourself. Other ailments commonly found in the breed include heart murmurs, cataracts, hanging tongue (neurological inability to fully retract the tongue) and fly catching syndrome (a hallucinating condition).