Shih Tzu loose stools: beyond probiotic chews

So the probiotic chews didn't move the needle — that's actually pretty common, and it tells us something useful. Most of those chews contain low bacterial counts that don't survive the gut journey, or they address the wrong part of the problem altogether. Before I suggest anything else, a couple of quick questions: how long has your Shih Tzu had loose stools, is it constant or does it come and go, and has anything changed recently — food, environment, stress? Also, has your vet ruled out parasites or a food intolerance?

Six weeks is a proper trial, so you've done this right — the chews just aren't the right tool. Shih Tzus do tend toward sensitive digestion, and what you're describing sounds like ongoing gut irritation rather than a one-off infection. The issue with most chew-format probiotics is that the bacterial strains are often dead or present in quantities too small to colonise the gut. What you need is something with a much higher viable count and ideally a kaolin or prebiotic component to soothe the gut lining at the same time. Can I ask what she's currently eating — dry kibble, wet food, raw?

That's worth noting — grain-free diets have actually been linked to digestive issues in some dogs, and for Shih Tzus with sensitive stomachs, a plain, easily digestible kibble with rice or oats as a base sometimes works better than grain-free. That's a longer-term conversation to have with your vet. But for right now, the product I'd actually recommend is Protexin Pro-Kolin Enterogenic paste. It's a concentrated probiotic and prebiotic combined with kaolin, which actively calms gut inflammation. It comes in a syringe format so you're dosing it directly rather than hoping a chew does the job. It has a significantly higher bacterial count than any chew I've seen, and the kaolin component helps firm up stools while the gut flora rebalances. It's widely used by vets in the UK and you can get it on Amazon. Give it ten to fourteen days consistently — if there's no change at all after that, the issue is more likely dietary or something structural, and that needs a vet conversation rather than more supplements.

It's safe as a short course and you can use it longer term at a maintenance dose, but honestly I'd start with a two-week course and see if the loose stools resolve. If they do, you probably don't need to keep giving it indefinitely — a healthy gut should hold its own once rebalanced. If she keeps relapsing every few weeks, that's a sign something in her diet or environment is repeatedly disrupting things, and that underlying cause is worth identifying rather than just managing symptoms with a supplement on rotation. The paste format also makes dosing easy for a small dog — at three years and a typical Shih Tzu weight you'll be using a small amount per day.

That's exactly the right approach. Sort the acute problem with Pro-Kolin, then look at the diet as the longer game. Most recurring digestive issues in small dogs come down to what they're eating day to day, and getting that right tends to make supplements unnecessary. Good luck — hope she's more comfortable soon.