If you’re prone to cold sores (also known as fever blisters), you know that the sooner you can apply a remedy—ideally, at the very first sign of tingling or pain—the shorter the duration of the sore and the milder the symptoms are likely to be.

If you have docosanol (Abreva)—an FDA-approved cold sore medication available without prescription that shortens healing time—great! Other remedies may also help, including deglycerized licorice cream and lomatium glycerite, both available from health-food stores and online. But if you don’t have Abreva and can’t get to a drugstore or health-food store immediately, what do you have on hand that will help?

A simple, effective remedy that works just as well as Abreva is as close as your home or office fridge or any place selling coffee (such as those Starbucks that are just about everywhere). It’s whole milk.

Cold sores are most commonly caused by herpes simplex virus. The sores are clusters of tiny, fluid-filled blisters on and around the lips, chin, cheeks or the inside of nostrils. The sores typically heal on their own over the course of two to four weeks. But during that period they can be miserable, as the painful blisters break, ooze and form a crust. Nearly all of us get exposed to the virus and nearly everyone has it in his/her body—80% of adults age 50 and older. Once you get it, you have it for life. But just having the virus in your body isn’t a problem. In fact, most of the time it stays dormant—until something, such as stress or a cold (hence the name), triggers an outbreak and you get a sore.

The trick to dealing with cold sores is to strike as soon as the telltale tingling lets you know that you’re getting one.

Why whole milk helps: Whole milk contains a protein called lactoferrin, which helps to fight against the herpes simplex virus. Whole milk also includes conjugated linoleic acid, a fatty acid that has antiviral properties that speed the healing process. (Reduced-fat milk will not be as effective—it also contains lactoferrin but has only tiny amounts of milk’s fatty acids.)

What to do: Soak a cotton ball in cold milk, and hold it on top of the blister for 10 minutes. Repeat as needed for three or four days This approach can keep ripening blisters from emerging, and the sore should be gone or nearly so after four days.

Bonus: In addition to its therapeutic compounds, the chill of the milk helps ease the tingling as soon as you apply it. (Applying ice to the cold sore can be soothing, too.) You may also want to sip a cup of tea spiked with one-half teaspoon of turmeric throughout the day. Turmeric contains curcumin, which has natural antiviral properties—more helpful healing from the inside out for the troublesome sore!