I am a big suffer of cold sores, the disgusting annoying things they are. I was warned off big time against both zorivax (and all cold sore creams) and lyosine tablets when I was pregnant. I use ice and a product called carmex. It can be found in the same section as your lip balms and it is in a little yellow tub similiar to blistex. It is also great for cracked lips too. Best of luck getting them all cleared up. Oh and thanks for the yoghurt tip. Next cold sore I'm going to scoff down yoghurt too.