The purpose of this study is to demonstrate the safety and efficacy of NB-001 in subjects with recurrent herpes labialis (RHL).

This is a randomized, double-blind, two arm, parallel-group, vehicle-controlled, multi-center study of NB-001. The study is designed to demonstrate the safety and efficacy of NB-001 in subjects with RHL. Approximately 850 subjects who meet all eligibility criteria will be randomized in the study. Subjects will begin treatment as soon as they experience the onset of cold sore symptoms. Treatment will be applied 5 times daily, approximately 3-4 hours apart while awake. Treatment will continue until the investigator assesses the primary lesion complex as healed or a maximum of 4 days.

Clinic visits will occur on a daily basis until the investigator determines that the primary lesion complex has healed or a maximum of 15 clinic visits. At daily clinic visits, the investigator will make efficacy assessments of the primary lesion complex; safety and tolerability assessments of NB-001 following topical administration will also be assessed daily. Subjects will make daily assessments of therapy.

At the End of Study, the investigator will make a global assessment of therapy. The subject will make global assessments of therapy and social impact.

Inclusion Criteria:

• A healthy man or woman 18 years of age or older. Women who are pregnant, lactating or may become pregnant may (at the investigator's discretion) be included in the study.
• Have recurrent herpes labialis as defined by a history of three (3) or more cold sore recurrences on the lips and/or skin surrounding the lips in the previous 12 months;
• Have the majority of their cold sore recurrences preceded by a well defined history of prodromal symptoms.

Exclusion Criteria:

• Subjects with severe chronic illness
• Received (within the last 6 months) or receiving chemotherapy;
• Significant skin disease on the face
• Previously received herpes vaccine;
• Active alcohol or drug abuse;
• Prior randomization into any NanoBio study;
• Known allergies to topical creams, ointments or other topical medications.