My post will give you hope of getting rid of them or at least cutting them down dramatically. I started getting cold sores after i kissed a guy who had them years ago. Being it is considered herpes simplex 1, i got a prescription for Acyclovir ( used mostly for genital herpes) and took one a day and it helped to keep the cold sores at bay, but i would still get them often, especially during illness or stress. Well i accidentally found something that worked <u>wonders</u> for keeping them from constantly creeping up. I started using <b>L-Lysine </b>for hemoptysis problems and i noticed on days i forgot to take the Acyclovir i didnt get any cold sores. So i finally stopped taking the Acyclovir completely and i dont get cold sores at all like i used to. I sometimes get a little one that will try to creep up , and if i up my intake of L-Lysine it goes right away. I take 1000 mg. twice a day of L-Lysine . I will up it by 1000 mg. if i am having hemoptysis problems or cold sore problems, but i barely have cold sore probs. at all anymore. I think with having cf our immune system isnt the best and something like herpes simplex 1 ( which is what usually causes cold sores) can be easily affected by it. Then again i also know perfectly healthy people who get cold sores all the time, so........ no i dont think its cf specific.