Chlorhexidine
"Every time I bite my cheeks -- which happens fairly often as I am a clumsy chewer -- the injury turns into a painful ulcer lasting a week. I would typically spend about half of my month with them. Aggressive rinsing with other forms of mouthwash could sometimes help a bit. 



Chlorhexidine gluconate is extremely effective at preventing and healing these ulcers. I can simply use one dose after an injury and never have a problem. If I ignore one long enough to form a small ulcer, two doses a day apart will immediately reverse its course toward healing. Now I never have to live with that mouth pain.



I have experienced no side effects."