Jaundice (icterus) is the yellow discoloration of the skin and mucous membranes (gums, rim of eyelids, whites of eyes, inner vulva), that occurs due to the accumulation of certain yellow blood pigments that become visible in these areas.

Interestingly, horses off their feed for several days also often accumulate these pigments and thus show yellowing of the gums, whites of the eyes and even the skin. Mild yellowing of tissues can also be a normal finding in otherwise healthy horses that graze on green pasture, due to ingestion of certain plant pigments in large quantities.

But it is also important to know that jaundice may be associated with a variety of severe diseases, especially those involving destruction of red blood cells, or liver disease. Horses suffering from these disease processes also tend to exhibit other signs of illness, especially depression, weight loss and loss of appetite.