2 doctors weighed in:

Should acyclovir (zovirax) 400 mg work on cold sore?

2 doctors weighed in
Dr. Brian Affleck
ENT - Head & Neck Surgery
1 doctor agrees

In brief: Cold sore

Acyclovir is a drug used to treat herpes virus infections.
Many cold sores are caused by herpes virus and will respond to such treatment. However, not all cold sores are caused by herpes. In this case, the cold sore may not respond to the treatment. The good news in all this, most cold sores get better within a couple of weeks, even without treatment. Keep it moist with ointment. This helps.

In brief: Cold sore

Acyclovir is a drug used to treat herpes virus infections.
Many cold sores are caused by herpes virus and will respond to such treatment. However, not all cold sores are caused by herpes. In this case, the cold sore may not respond to the treatment. The good news in all this, most cold sores get better within a couple of weeks, even without treatment. Keep it moist with ointment. This helps.
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