Skip main navigation


Search info


What are cold sores?


Cold sores and fever blisters are painful, fluid-filled blisters on the lips or nearby skin. A virus called herpes simplex type 1 causes them. Cold sores are contagious and are spread by touch. They often appear when you're under stress or sick. Sun exposure and minor cuts and scrapes can reactivate them. Cold sores are usually able to heal in 10 to 14 days without treatment.

Many people in the United States are infected with the oral herpes virus but have no - or infrequent - outbreaks of cold sores. While cold sores are caused by a type of herpes virus, they are not a sign of genital herpes.

The virus is never actually "cured" but the outbreak of the sores is what can be treated with alternative therapies.

You can treat cold sores with herbal, over-the-counter, or prescription treatments. You can try to apply cold or heat to help ease pain caused by the painful sores. Talk to your doctor if over-the-counter remedies don't work for you.

Alternative therapies

There are some alternative therapies commonly used to treat cold sores, but there isn't sold proof that they work. The supplements L-lysine and lactobacillus are used to help treat cold sores. Their side effects aren't known. L-lysine is usually taken as 1000 mg one to three times a day. There isn't a recommended dose for lactobacillus. L-lysine and lactobacillus haven't been directly compared to over-the-counter and prescription treatments for cold sores. You can try applying cold or heat to help ease the painful sores.

Over-the-counter treatments

An over-the-counter medicine called Abreva® (docosanol) may help cold sores heal faster and reduce the bothersome symptoms associated with them. Studies show that Abreva® can help cold sores heal one day sooner than when no drug is used. When applied at the earliest stages of an outbreak, Abreva® may help prevent cold sores and blisters from forming.

Lip balms

Other over-the-counter products can help relieve the discomfort of cold sores, but they don't help them go away faster. To relieve dryness and help keep the sores soft, use products containing the ingredients allantoin, petrolatum, or cocoa butter. Examples of these products include Blistex® and Carmex®.

Pain relief

For cold sore pain relief, try products that contain local anesthetics. Anbesol® cold sore ointment contains benzocaine, and Zilactin® ointment contains benzyl alcohol to relieve pain. You can also use pain relievers such as acetaminophen (Tylenol®) or ibuprofen (Motrin® and Advil®).

If a cold sore becomes infected, apply an antibiotic ointment such as Polysporin® three to four times a day. If sun exposure tends to reactivate your cold sores, use a lip sunscreen. Talk to your doctor about prescription therapy if over-the-counter medicines don't relieve your discomfort or if the sores remain for more than 14 days.

Prescription cold sore treatments

There are various prescription treatments for cold sores and fever blisters. Talk to your doctor about prescription therapy for treating your cold sores if over-the-counter medicines don't provide relief. Denavir® (penciclovir), Valtrex® (valacyclovir) and Zovirax® (acyclovir) all are used to treat the herpes simplex type 1 virus. They help cold sores heal an average of 12 hours faster than when no drugs are used. These products must be used three to six times a day for four to seven days to be effective.

These medicines will not prevent an outbreak of cold sores. But they can help reduce symptoms if you start using one as soon as you feel a cold sore develop. If you have herpes simplex type 1, keep one of these medicines on hand to allow prompt treatment.

Back to Ask a Pharmacist


Answers to questions regarding information about medications or health conditions are not for diagnostic or treatment purposes and are not conclusive as to the presence or absence of any health condition. Consult your physician for diagnosis and treatment of your medical condition. The information provided is not a substitute for medical advice. Advances in medicine may cause this information to become outdated, invalid or subject to debate. Professional opinions and interpretations of the scientific literature may vary. Walgreens' terms of use and general warranty disclaimer apply to all services provided. If you are in need of immediate medical attention, contact your physician, poison control center or emergency medical professional. If you need to speak with a pharmacist for non-emergency matters, contact your local Walgreens pharmacist or call a pharmacist toll-free at 1 (877) 250-5823.

Balance Rewards for Healthy Choices

20 Points
20 Points

Now you can track your blood pressure and blood glucose.

Start earning points Go Arrow