Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Cold Sores

By Debra Jaliman, MD

A large proportion of people living in the United States have been exposed to the herpes simplex virus, so it’s no surprise that dermatologists see people with cold sores every week. What is surprising is the myths that surround cold sores.

First of all, cold sores are not canker sores. Cold sores are always on the lip; canker sores, also known as aphthous ulcers, appear inside the mouth and are NOT contagious.

Cold sores are caused by the herpes simplex virus, either type I or type II (type II is also responsible for genital herpes). Cold sores are EXTREMELY contagious. People with cold sores should never share cups, lipsticks or towels and should refrain from kissing children, pregnant women, anybody who is immuno-compromised, and especially cancer patients on chemotherapy or radiation therapy, for whom a herpes infection can be life-threatening.

Cold sores are so contagious they can easily spread to other parts of the body. I always tell patients to stop using towels on their faces when they have cold sores, because towels can carry the infection to the eyes, and a herpes eye infection is quite serious and painful. Use paper towels instead.

Herpes infections are fairly easy to treat. Over-the-counter topical anti-virals like Abreva work relatively well, but the most effective treatment is prescription anti-viral pills such as acyclovir and valcyclovir. Very important to keep in mind: if you have cold sores for the first time, run, don’t walk to your doctor. I cannot emphasize this enough — if the first outbreak is treated promptly with prescription anti-virals, it is possible to kill the virus and prevent future recurrences.

Once the herpes virus takes hold, it becomes a recurring problem. Several factors can trigger cold sores:

-          Stress, whether emotional or physical, such as from surgery or medical treatments.

-          Ultraviolet light. Anybody with cold sores should always use lip balms with sunscreens. After a cold sore episode, throw away the lip balm and get a new one; otherwise, you’ll just keep re-infecting yourself.

-          Colds and flu.

-          Extremes in temperature, which is why people tend to have outbreaks in winter and summer.

People with recurring cold sores should always travel with a supply of prescription anti-virals. When taken at the first sign of an outbreak, usually a tingling or burning sensation on the upper lip, the pills might be able to head off a full-blown episode.

Taking lysine as a preventative is still controversial. The latest studies seem to show that taking lysine regularly may prevent or at least reduce outbreaks, but it does not appear to be as effective once the cold sore actually appears. With that in mind, people who have already experienced cold sores might consider taking lysine daily. The recommended dose for adults is 1,000 mgs daily, but check with your doctor first to see if lysine might conflict with any medications.

Bottom line: Herpes should be taken seriously, so see a doctor immediately to get the right medication.


The opinions expressed in WebMD Second Opinion are solely those of the User, who may or may not have medical or scientific training. These opinions do not represent the opinions of WebMD. Second Opinion are... Expand


Subscribe to free WebMD newsletters.

  • WebMD Daily

    WebMD Daily

    Subscribe to the WebMD Daily, and you'll get today's top health news and trending topics, and the latest and best information from WebMD.

  • Men's Health

    Men's Health

    Subscribe to the Men's Health newsletter for the latest on disease prevention, fitness, sex, nutrition, and more from WebMD.

  • Women's Health

    Women's Health

    Subscribe to the Women's Health newsletter for the latest on disease prevention, fitness, sex, diet, anti-aging, and more from WebMD.

By clicking Submit, I agree to the WebMD Terms & Conditions & Privacy Policy and understand that I may opt out of WebMD subscriptions at any time.

URAC: Accredited Health Web Site TRUSTe online privacy certification HONcode Seal AdChoices