I have been taking imuran since 11/06. I had sores in mouth and sometimes nose prior to imuran and since imuran. Oral uncers are a notorious symptom of autoimmune problems. I have a friend who takes Valtrex for these (she has lupus) but valtrex did nothing for me. I also have dry mouth (sicca syn). I have found a few things help a little: drink frequent sips of water--avoid pop,even diet, due to acid. I found my partial which has a lot of metal on it aggravates the sores, so I recently got a plastic flipper (looks just like partial but is all plastic--can't eat in it but gets the metal out of my mouth most of the time. Metal makes my sores worse. I lived on majic swizzle all last summer. Also, if there is any chance you have any gastric reflux, take zantac, prilosec, or something cause I have found acid indigestion makes the sores worse. I finally got rid of mine when I took a round of difulcan (spelling?). Also use biotene dry mough toothpaste and mouthwash--rec by dentist. And all of the other stuff I have listed above have lelped also. Good luck. Nancy