Herpes simplex is a common viral infection of the skin or mucous membranes. The lesions caused by this infection are often painful, burning, or pruritic, and tend to recur in most patients. Short-term treatment with acyclovir can accelerate the healing of an acute outbreak, and continuous acyclovir therapy is often prescribed for people with frequent recurrences. While this drug can reduce the recurrence rate by 60-90 percent, it can also cause a wide array of side effects, including renal failure, hepatitis, and anaphylaxis. Safe and effective alternatives are therefore needed. There is evidence that certain dietary modifications and natural substances may be useful for treating active Herpes simplex lesions or preventing recurrences. Treatments discussed include lysine, vitamin C, zinc, vitamin E, adenosine monophosphate, and lemon balm (Melissa officinalis).