L-Lysine is an amino acid and can help treat the symptoms of FHV-1 (Feline Herpesvirus), upper respiratory infection (URI - coughing, sneezing, etc.) and conjunctivitis (eye discharge, swollen, irritated, red, cloudy).
The problem with the virus is it lays dormant for periods of time and then starts reproducing causing flare-ups. In cats, seasonal sneezing and conjunctivitis coincide with seasonal changes in spring and fall or during stressful holiday periods like Christmas. Use L-Lysine during these times to decrease viral reproduction and shedding.
You can buy the regular L-Lysine powder but the Tomlyn brand flavors theirs and my cat loves it!