Canker sores can have many causes, including but not limited to the Herpes 
virus.  I used to get outbreaks of these sores, assumed they were caused by 
Herpes, and tried using lysine but found it ineffective.  If caused by Herpes, 
lysine is effective, but I am now certain mine had some other cause.  I also 
had outbreaks of what I now know was perleche, but thought was some form of 
herpes outbreak.  Turns out it was caused by yeast, and, once established, the 
only cure was a nystatin cream, CS wouldn't stop it once it took root.  

I have not had outbreaks of either for a couple of years, probably due to 
better diet and change of environment.  
The following page has some good information on canker sores:
http://www.animated-teeth.com/canker_sores/t1_canker_sores.htm

If you want to know what perleche looks like, here are some very graphic photos:
http://www.dermnet.com/thumbnailIndex.cfm?moduleID=18&moduleGroupID=556&groupIndex=0&numcols=0

I guess my point is, I thought for many years that I had some form of Herpes, 
but did not, so it is important to get an accurate diagnosis in order to treat 
the problem effectively.

Del

From: Brooks Bradley 
  To: silver-list@eskimo.com 
  Sent: Tuesday, February 12, 2008 9:51 PM
  Subject: Re: CS>Cold Sores


  Cold sores are caused by Herpes Simplex I (HVS-1), a virus which is present 
in a large portion of the human population. While quite vexing in some cases, 
it, alone, is not life threatening....nor a major health challenge in its 
principal presentations. The herpes family of viruses may be driven quiescent, 
temporarily, but are lifetime companions of the afflicted. This is typical of 
viruses in general. There are many treatments for acute outbreaks....most 
palliative in nature. One protocol we have found to be particularly effective 
is the employment of lysine (many use the ointment applied topically) taken at 
approximately 300 mg daily, together with the topical use of a lysine/DMSO 
solution. The favored (by us) solution strength is 20% DMSO (by volume) mixed 
with a super-saturated solution of lysine......applied to the blisters 
  once each hour the first day and once each 2 hours thereafter---until the 
eruptions are controlled (usually by day 3). One convenient method for making a 
super-saturated lysine solution is by placing about one ounce of water in a 
small glass container and adding powdered lysine until no more will go into 
solution....then add 20% (by volume) full strength DMSO. It is quite easy to 
use cotton Q-tips to apply the solution to the blisters. One suggestion; try to 
avoid licking your lips for about 2 minutes after applying the solution, but be 
sure not to lick them for at least one minute-----to insure an acceptable 
tissue penetration of the solution. One ounce of this solution will be 
sufficient to treat many "cold sores". This, particular, solution has a very 
long shelf life. 
  If any of the lesions are infected at the time of treatment, just add 10% (by 
volume) CS at 10 ppm strength....to the parent solution. 
  If you are a "physical coward" (as am I), the application of any quality aloe 
vera gel 
  product....a few minutes prior to applying the DMSO X Lysine 
protocol-----will yield welcome 
  pain reduction. 
  Sincerely, Brooks Bradley.