Calici virus is another serious viral respiratory disease which also causes painful ulcers in the mouth. (morenapethospital.com)
Cats can also get painful ulcers on the cornea of the eye or in their mouth. (lovinmypup.com)
She confided in us that she was a cancer survivor and recalls the very painful mouth ulcers she would get resulting from the cancer treatment (apparently conventional cancer treatment ie chemo causes painful ulcers in the gum and cheek tissue). (wellnessmama.com)