Until very recently, potential cases of Feline Infectious Peritonitis (FIP) made my heart sink. This heart-breaking disease is frustratingly difficult to diagnose, and when we get close to confirming a case pre-mortem, it is almost invariably fatal. That is still the case in most of the world, but in the UK (and Australia), we now have legal Remdesivir. This is a wonderful positive spin-out from the Covid pandemic. However, this new treatment is not without pain and cost, so making the correct diagnosis is essential. This webinar will consider all of the current diagnostic options, plus their limitations, enabling participants to make pragmatic and realistic diagnostic plans. While discussing how best to use Remdesivir, the papers that support its use, unpublished findings, and legal considerations, we will also examine other treatment options, including interferon omega, polyprenyl immuno-stimulant, and 3C-like protease inhibitor (GC376), and their potential role in these cases.