Cat blood in urine: what works when supplements fail

Blood in urine that persists after two different supplements is a sign that supplements alone aren't addressing the underlying issue — and in a seven-year-old male cat, that's worth taking seriously. Urinary problems in males can escalate quickly, and hematuria specifically points toward either crystals, inflammation, or early kidney/bladder disease that really needs a vet diagnosis to pin down. Diet is almost always part of the answer, but you need to know what you're treating first. Can you tell me: has your cat been seen by a vet for this current bout of bleeding, what were the two supplements you tried, and what is he eating day-to-day right now?

That's really helpful context. Cystease is an anti-inflammatory and Zylkene is a calming supplement — both are reasonable choices for FIC, but neither one addresses the dietary side, which for a male cat is arguably the most important lever you have. Whiskas wet food is high moisture which is good, but the dry Royal Canin in the mix — unless it's the Urinary SO variety specifically — is likely contributing to concentrated urine, which keeps the bladder irritated even when stress is managed. What dry Royal Canin is he on, and roughly what proportion of his diet is dry versus wet?

That's almost certainly a big part of what's keeping the problem going. The Exotics formula isn't formulated for urinary health, and a 60/40 split in favour of dry means his urine is chronically more concentrated than it should be — that irritates the bladder wall continuously, which in FIC cats becomes a cycle that's very hard to break. The fix I'd suggest is switching him entirely to Royal Canin Urinary SO wet food. It's specifically designed to dissolve struvite crystals, reduce urine concentration, and create a urinary environment that's hostile to crystal formation. It comes in pouches and in loaf tins, both of which tend to go down well with cats who've been on Royal Canin dry, because the flavour profile is familiar. The goal is to get him off dry completely or as close to it as possible — moisture is the single biggest dietary factor in male cat urinary health. Royal Canin Urinary SO wet is available on Amazon UK in multipack pouches and is straightforward to transition to over about a week by mixing with what he currently eats.

On the fussiness — because he's already eating Royal Canin, you're in a better position than most. The Urinary SO wet has a similar flavour base to the dry he knows, so a slow transition over 7 to 10 days, mixing increasing amounts of the new food in with the Whiskas he already accepts, tends to work well. Warming the food slightly can also help if he's reluctant. On the vet question — yes, absolutely go back. Three weeks of visible blood warrants a follow-up, particularly because they should be checking whether crystals are present on ultrasound or urinalysis if they haven't already. The diagnosis of idiopathic cystitis is essentially a diagnosis of exclusion, and it's worth confirming there isn't something structural or crystalline driving this. Diet change and a vet review together is the right combination here, not one or the other.

Good plan. When you speak to the vet, it's worth specifically asking them to confirm whether crystals were found and whether the urine pH was tested — that will tell you which direction the diet needs to go if the Urinary SO alone isn't enough. The wet food switch is the right first move regardless. I hope he improves quickly — persistent symptoms in a male cat are always worth staying on top of.