Read the Patient Information Leaflet if available from your pharmacist before you start using acyclovir and each time you get a refill. If you have any questions, ask your doctor or pharmacist.Use this medication at the first sign of infection (such as tingling, burning, redness). Wash your hands with soap and water before and after applying this medication. Clean and dry the affected areas before applying the medication. Apply to the affected area and rub in gently as directed by your doctor, usually 5 times a day (every 3 to 4 hours) for 4 days for cold sores. Apply enough cream to cover all affected areas (red/tingling/burning areas, sores).Apply to skin only. Do not apply this medication in the eyes or nose, inside the mouth, or inside the vagina. If you do get medication in those areas, flush with plenty of water.Dosage is based on your medical condition, type of infection, and response to treatment. Do not use this drug more often or for longer than prescribed.Use this medication regularly to get the most benefit from it. This medication works best when the amount of drug absorbed by the skin stays at a constant level. Use this drug at evenly spaced intervals. To help you remember, use it at the same times each day.To prevent washing off the medication, do not bathe, shower, or swim right after applying it.If applying to genital herpes sores, use a finger cot or rubber gloves to avoid spreading the infection.Do not apply other skin products (such as drugs, cosmetics, sun screens, or lip balms) unless told to do so by your doctor. Do not cover the area with plastic or waterproof bandages unless told to do so by your doctor.Cold sores (herpes) can spread easily. Acyclovir cream does not prevent the spread of herpes. Avoid close physical contact with others (such as kissing) during an outbreak until the cold sores have completely healed. Also, try not to touch the cold sore, and wash your hands if you do touch the cold sore.If you are using acyclovir for treatment of genital herpes, it is important to follow safe sex practices to reduce the risk of giving herpes to your partner, even if there are no symptoms present. Always use a condom made of latex or polyurethane. When you have symptoms or are experiencing an outbreak, do not have sexual contact with your partner.Tell your doctor if your condition lasts or gets worse after treatment is finished.