This medication is used to treat a variety of fungal skin infections such as ringworm, athlete's foot, and jock itch. This medication is also used to treat a skin condition known as pityriasis (tinea versicolor), a fungal infection that causes a lightening or darkening of the skin of the neck, chest, arms, or legs. Terbinafine is an antifungal that works by preventing the growth of fungus. Do not use this medication for the treatment of fungal nail infections. How to use Lamisil Top Use this medication on the skin only. Clean and thoroughly dry the area to be treated. Apply a thin layer of the medication on and around the affected area, usually once or twice daily as directed on the product package. If you are uncertain about any of the information, consult your doctor or pharmacist. Wash your hands after using unless the area being treated includes the hands. Do not wrap, cover, or bandage the area unless directed to do so by your doctor. Do not apply the medication in the eyes, nose, or mouth, inside the vagina, or on the scalp. If you do get the medication in those areas, flush with plenty of water. The dosage and length of treatment depends on the type of infection being treated. Do not apply more often or use longer than directed. This may increase the risk of side effects. Use this medication regularly to get the most benefit from it. To help you remember, use it at the same time(s) each day. Continue to use this medication until the full treatment period is finished, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection. Your condition may continue to improve after the full treatment is finished. It may take several weeks after treatment for the infection to completely heal. Inform your doctor if your condition worsens or does not improve within 2 weeks for jock itch and ringworm and within 4 weeks for athlete's foot.