This cream helps stop herpes simplex virus causing a sore. Rub it in as soon as you feel anything – some people use it daily as a preventative. People on our trial (72% success rate) said it prevented the outbreak from developing. It is made in Germany from melissa officinalis (lemon balm) in an emollient base. Melissa contains molecules that block receptor sites on the skin cells and prevent the virus getting into the cells where it multiplies.