KCS in man is often associated with a systemic disease whose pathogenesis is still obscure. A spontaneous animal model resembling Sjögren's syndrome has been developed in the NZB and NZB-NZW mouse. Other spontaneous animal models analagous to lupus erythematosis and polyarteritis have been found in dogs and Aleutian mink, respectively. Studies of the eyes and lacrimal glands in such animals, and in dogs with distemper, should be pursued. A viral etiology is implicated in each of the models. The roles of both the main and accessory lacrimal glands in normal and KCS eyes have been discussed, as well as drug-induced KCS and opportunities for its further investigation and treatment.