Prebiotic fiber for cats with loose stools

So your vet has recommended adding prebiotic fiber to help manage your Birman's chronic loose stools — that's a really practical direction, and it works well alongside an existing diet rather than overhauling everything. Digestive sensitivity in cats is often driven by food intolerance rather than true allergy, and prebiotic support helps stabilise the gut microbiome over time. Before I point you to the right product, a couple of quick questions: is your Birman on a wet food, dry food, or a mix right now, and did your vet mention a specific type of fiber or just say to add a prebiotic supplement generally?

That's helpful — a year of on-and-off loose stools is long enough that you want something consistent and proven rather than experimental. Given your vet's guidance and the fact that she's already on a mixed diet you don't want to disrupt, I'd recommend Purina Pro Plan FortiFlora for Cats. It's the most widely vet-recommended probiotic and prebiotic supplement in the UK, comes in individual daily sachets you just sprinkle over her food, and has solid clinical evidence behind it for exactly this kind of chronic low-grade digestive instability. It's palatable enough that most cats take to it without fuss. One sachet per day mixed into her wet food is the standard approach.

Yes, it's designed for long-term daily use — that's actually one of the reasons vets reach for it first. There are no known issues with extended supplementation, and many cats stay on it indefinitely with good results. Some owners see improvement within two to three weeks; others find it takes a full month before stools consistently firm up. Given she's seven and has had this going on for a year, I'd give it at least four weeks before evaluating whether it's doing enough on its own.

It'll work with whatever she's currently eating — FortiFlora isn't food-dependent. That said, if you find she plateaus after a month and stools are still inconsistent, it might be worth revisiting the wet food itself, as some formulas with high fish content or lots of additives can sustain low-grade gut irritation. But start with the supplement as your vet suggested, and see how she responds before changing anything else. No need to complicate it.