My lil girl suffers from calici, which is in other words is cat herpes. She was a feral rescue that I took in and that's where she picked it up from. They have it their entire life, but it is manageable. Once or twice a year when she has flare-ups, her vet will have her on a 30-day regimen of azithromycin which will kick it until next time. Symptoms are cold-like - congestion, stuffyness, watery eyes ('eye' in her case cause she only has one), crusty nose, sneezes, etc. My vet recommends Viralys daily as something to keep the symptoms at bay and it seems to work. It's got l-lysine, which helps to boost their immune system. Some say it keeps the symptoms of calici either less likely to occur or less severe when they do show up. It's about $24 a bottle, but well worth it for their health. I give it once a day off the tip of my finger in the morning before breakfast. The bottle lasts me about 2 months. It's maple flavored which may seem odd, but she loves it. We call it her 'morning maple.' The flavor may not appeal to all cats, as her brothers show no interest in it so luckily they don't need it. I'll forever give it to her as it can only help with her situation.