A Double-Blind, Randomized, Placebo-Controlled Study of Topical VDO for the Treatment of Herpes Simplex Labialis

Inclusion Criteria: * Male or female in the age group 20 to 75 years old. * History of recurrent herpes labialis with at least one recurrence occurred during the past twenty-four months. * Onset of prodrome, erythema or vesicle within 72 hours of initiation of treatment with the study drug. * Subjects with previous herpes simplex labialis episodes must be healed for at least 14 days before the baseline. * Must be willing and able to participate and to provide written informed consent. * Female subjects of childbearing potential must have a negative pregnancy test at screening and agree to use a proper contraceptive method during the study. Exclusion Criteria: * Women during pregnancy, lactation or breastfeeding. * Subjects using topical steroids on or near the face or systemic (oral, intravenous) steroids within 7 days prior to study drug administration; use of inhaled or nasal spray steroids does not exclude a subject from the study. * Subjects have used anti-viral agents or NSAID in the preceding 7 days. * Subjects are unwilling to stop for using topical medical, OTC, cosmetic or facial skin care products in or around the oral area during the study period. * Subjects with immunodeficiency disorders such as human immunodeficiency virus (HIV) infection or receiving cancer chemotherapy. * Subjects who have a history of hypersensitivity to diclofenac, lidocaine or propylene glycol. * Subjects who have a known hypersensitivity to local anesthetics of the amide type, diclofenac, aspirin, or other NSAIDs. * Subjects who are taking antiarrhythmics drug during screening visit； * Subjects who have a history of asthma, urticaria, or other allergic-type reactions after taking aspirin or other NSAIDs. * Subjects who use during the perioperative period in the setting of coronary artery bypass graft (CABG) surgery within 6 months before the study drug using. * Subjects have history of substance abuse or psychiatric illness that would preclude compliance with the protocol. * Subjects who have serious, unstable, or clinically significant medical or psychological conditions, which, in the opinion of the investigator(s), would compromise the subject's participation in the study (including clinically significant dehydration or unstable vital signs). * Subjects taking or having taken any other experimental drugs, drugs not approved in Taiwan, or participating in or having participated in other clinical studies in the 30 days prior to this clinical trial. * Subjects who are considered unreliable as to medication compliance or adherence to scheduled appointments, or inappropriate for inclusion determined by the investigators.