Your health care provider can usually diagnose cold sores just by looking at them. To confirm the diagnosis, your health care provider might take a sample from the blister for testing in a laboratory.


Cold sores often clear up without treatment in 2 to 4 weeks. Your doctor might prescribe antiviral medicine that may speed the healing process. Examples include:

  • Acyclovir (Zovirax).
  • Valacyclovir (Valtrex).
  • Famciclovir.
  • Penciclovir (Denavir).

Some of these products are pills. Others are creams you put on the sores several times a day. In general, the pills work better than the creams. For very severe infections, some antiviral medicines can be injected.

From Mayo Clinic to your inbox

Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. Click here for an email preview.

To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.

Lifestyle and home remedies

The cold sore ointment docosanol (Abreva) may shorten the healing time of a cold sore. At the first sign of symptoms, apply it to the affected skin as directed on the package. Use a cotton-tipped swab to put medicine on a cold sore. This helps prevent the spread of the sores to other parts of the body.

To ease the discomfort of a cold sore:

  • Try other cold sore remedies. Some nonprescription products contain a drying agent, such as alcohol, that may speed healing.
  • Use lip balms and cream. Protect your lips from the sun with a zinc oxide cream or lip balm with sunblock. If your lips become dry, apply a moisturizing cream.
  • Apply a compress. A cold, damp cloth may ease symptoms and help remove crusting. Or try using a warm cloth on the blisters to ease pain.
  • Rest and try pain relievers. Take nonprescription pain medicine if you have a fever or the cold sore is painful. Creams with lidocaine or benzocaine may offer some pain relief.

Alternative medicine

Studies about whether alternative medicine helps with cold sores have had mixed results. Some approaches that people use for cold sores include:

  • Lysine. An amino acid, lysine is available as an oral supplement and as a cream.
  • Rhubarb and sage. A cream combining rhubarb and sage may be about as effective as acyclovir (Zovirax) cream.
  • Stress reduction. If your cold sores are brought on by stress, you might want to try relaxation techniques. Examples include deep-breathing exercises and meditation.
  • Propolis. This is available as a 3% ointment. When applied early and often, it might shorten the duration of the breakout. This product is also called synthetic beeswax.

Preparing for your appointment

Cold sores often clear up without treatment in 2 to 4 weeks. Make an appointment with your primary care provider if your cold sores:

  • Are lasting or severe.
  • Return often.
  • Are accompanied by eye pain or gritty eyes.

What you can do

Before your appointment, you may want to list answers to the following questions:

  • Have you ever had these symptoms before?
  • Do you have a history of skin problems?
  • What medicines and supplements do you take regularly?

Below are some basic questions to ask your health care provider about cold sores.

  • Do I have a cold sore?
  • What treatment do you recommend, if any?
  • What self-care steps might ease my symptoms?
  • Can I spread this condition to others? For how long?
  • How do I reduce the risk of spreading this condition to others?
  • How soon do you expect my symptoms will improve?
  • Am I at risk of complications from this condition?
  • Can I do anything to help prevent another blister?

What to expect from your doctor

Your health care provider is likely to ask you a few questions. Being ready to answer them may reserve time to go over any points you want to talk about in-depth. Your health care provider may ask:

  • Could you sense a cold sore coming before you could see it?
  • Do your symptoms include eye pain or gritty eyes?
  • Does anything seem to bring on your symptoms?
  • Have you been treated for cold sores in the past? If so, what treatment helped the most?
  • Have you been under stress lately or had major life changes?
  • Are you pregnant?
  • Does your work or home life bring you into contact with infants or with people who have major illness?
Jan. 05, 2024
  1. AskMayoExpert. Cold sores (herpes simplex infection). Mayo Clinic; 2019.
  2. Dinulos JGH. Warts, herpes simplex, and other viral infections. In: Habif's Clinical Dermatology. 7th ed. Elsevier; 2021. https://www.clinicalkey.com. Accessed April 7, 2020.
  3. Herpes simplex. American Academy of Dermatology. https://www.aad.org/public/diseases/a-z/herpes-simplex-overview. Accessed April 7, 2020.
  4. Ferri FF, et al., eds. Herpes simplex. In: Ferri's Fast Facts in Dermatology: A Practical Guide to Skin Diseases and Disorders. 2nd ed. Elsevier; 2019. https://www.clinicalkey.com. Accessed April 7, 2020.
  5. Kermott CA, et al., eds. Canker sores. In: Mayo Clinic Book of Home Remedies. 2nd ed. Time; 2017.
  6. Kermott CA, et al., eds. Cold sores. In: Mayo Clinic Book of Home Remedies. 2nd ed. Time; 2017.
  7. Gibson LE (expert opinion). Mayo Clinic. April 6, 2015.
  8. Lemon balm. Natural Medicines. https://naturalmedicines.therapeuticresearch.com/. Accessed April 8, 2020.
  9. Lysine. Natural Medicines. https://naturalmedicines.therapeuticresearch.com/. Accessed April 8, 2020.
  10. Rhubarb. Natural Medicines. https://naturalmedicines.therapeuticresearch.com/. Accessed April 8, 2020.
  11. Propolis. Natural Medicines. https://naturalmedicines.therapeuticresearch.com/. Accessed April 8, 2020.
  12. Bauer BA, ed. Making wellness the focus of care. In: Mayo Clinic Guide to Integrative Medicine. Time; 2017.
  13. Klein RS. Treatment of herpes simplex virus type 1 infection in immunocompetent patients. https://www.uptodate.com/contents/search. Accessed April 8, 2020.
  14. Hargitai IA. Painful oral lesions. Dental Clinics of North America. 2018; doi.10.1016/j.cden.2018.06.002.