I have a friens who got a canker sore and after it went away he later got another one and they've just been more regular and recent. problem here?

Possibly Herpes: Try bht (butylated hydroxytoluene), 2000 mg per day (in divided doses). Bht is the most effective anti-herpes substance there is--cheaper, and more effective than the expensive drugs. See the free e-book, available on-line, wipe out herpes with bht, by steven fowkes. Bht is available in some health food stores, or on-line by many supplement companies.

Need correct diagnos: Canker sore can refer to, just about any ulcerative lesion of the lips or mouth. Herpes lesions usually recur in the same location, start with blisters then scab. Treat with antivirals. Herpangina is herpes affecting the lining over the bone such as gums and hard palate. Use antivirals. Aphthous ulcers or lichen planus occur on tongue, cheek, palate and tonsils and respond to steroids. See ent.