You may be able to continue your normal eating patterns. I take it without regard to food, and I've had no problems with digestion. I can't speak for everyone, but just give it a shot, and see what works for you. This is the first time I've gotten a canker sore (aphthous ulcer, not cold sore) and sore throat since starting the Tagamet treatment. I know what triggered it -- I went tanning. I ALWAYS flare with UV exposure, but I was hoping the Tagamet would ward it off. The ulcer already healed quite a bit overnight, so it's safe to say the Tagamet shortens the duration and severity. I don't feel sick. Normally a flare like this would last at least a week with several mouth ulcers and fevers. I feel fine, but I should probably stop tanning.