Calicivirus in cats is an extremely contagious viral infection with symptoms similar to upper respiratory infections (sneezing, nasal congestion, conjunctivitis), ulcers in the cat’s mouth or on the lips and nose, inflammation and fatigue. Because the virus may impair the cat’s ability to smell and taste, many cats will become anorexic. The mouth symptoms may appear similar to stomatitis, an autoimmune condition that causes mouth swelling, drooling and ulcers. Feline calicivirus (FCV) readily mutates, so vaccines are not always effective in preventing the spread of the virus. Calicivirus can live for up to a month, so it is very important to disinfect any surfaces that may have come in contact with the virus. Calicivirus can be spread through saliva or secretions from the nose or eyes. It is most common in shelters and multi-cat households. Natural treatment for feline calicivirus includes supplements for immune support along with feeding a low carbohydrate, novel protein diet.