Lysine competes with another amino acid, arginine, that herpes virus must have in order to reproduce. Lysine has been demonstrated to decrease the severity of ocular symptoms associated with herpes virus infection (1) and reduce viral shedding during periods of disease recurrence (2). Depending on symptoms, other medications such as topical antiviral drugs, topical polysulfated glycosaminoglycans, topical nonsteroidal anti-inflammatory drugs or topical interferon may be used. In some cases the ocular diseases resulting from feline herpes virus may require surgical intervention. The key to managing the clinical signs associated with feline herpes virus is controlling the cat's environment. Cats exposed to multiple cats (indoor-outdoor cats), cats in multiple cat households, or cats that are frequently introduced to new cats are difficult to keep disease free. Reducing stress by maintaining a stable routine is helpful in preventing recurrences of disease. Keep in mind that it is the nature of the virus to see recurrences of the disease and periodic treatment is often necessary.