Sulfasalazine is used to treat inflammation of the bowel. Keratoconjunctivitis sicca (KCS, dry eye) may occur with long-term use of sulfasalazine. Stop giving the medication and consult your veterinarian if your pet experiences discharge from the eye, redness of the eye, squinting, or other signs related to the eye. Consult your veterinarian if your pet experiences depression, vomiting, loss of appetite, pale gums, tiredness, bleeding tendencies, fever, increased thirst or urination, skin rashes, itchiness, or jaundice (yellowing of the gums, skin, or whites of the eyes), increased rate of breathing, weakness, confusion, seizures, or facial swelling while being treated with sulfasalazine.  Your pet's bowels will most likely take on the color of the medication.