Herpes labialis is the most common recurrent manifestation of herpes simplex. The purpose of this study is to check the non-inferiority efficacy and safety of penciclovir 10mg/g as treatment for Herpes Labialis in comparison to acyclovir 50mg/g.

Study design:

• Double blinded non-inferiority prospective parallel-group, intend to treat trial.

Study design:

• Experiment duration: 10 days
• 3 visits (days 1,5 and 10)
• Erythema, papule, vesicle, ulcer, crust and healed skin evaluation
• Adverse events evaluation

Inclusion Criteria:

1. Patients must be able to understand the study procedures agree to participate and give written consent.
2. Patients with clinical diagnosis of recurrent herpes labialis and are in the prodromal period (stinging, itching, burning and erythema) at the onset of signs / symptoms in the last 12-24 hours;
3. No history of reaction to topical products;

Exclusion Criteria:

1. Pregnancy or risk of pregnancy.
2. Lactation
3. Use of anti-inflammatory or immunosuppressive drugs (last 30 days prior to the study.)
4. Sunlight over exposure in the last 15 days.
5. Any pathology or past medical condition that can interfere with this protocol.
6. AINH use, hormonal anti-inflammatory, analgesic and immunosuppressive drugs (in the last 30 days and during the study);
7. Patients with immunodeficiency and/or immunosuppressive disease;
8. Sunlight exposure in the last 15 days;
9. Hypersensitivity to components of the formula;
10. Other conditions deemed reasonable by the medical investigator as to the disqualification of the individual from study participation.