Flea shampoo not working on Shih Tzu? Fix it fast

Flea shampoo is one of the most common reasons infestations keep coming back — it kills adult fleas on the dog in the moment, but it has zero residual action and does nothing for the eggs and larvae already deep in your carpet. That's the real problem here. Before I point you in the right direction, a couple of quick questions: is your Shih Tzu around the standard size — so roughly 4 to 7 kg — and how widespread does the infestation feel right now? Are fleas turning up in multiple rooms, or mostly one area?

Three months of monthly shampoos and still seeing live fleas straight after bathing — that tells me exactly what's happening. The carpet is acting as a continuous hatchery. Flea eggs take up to two weeks to hatch, so even a perfect treatment on your dog today will be undone within days if the carpet isn't dealt with at the same time. Have you used any kind of home spray or household flea treatment at all, or has it purely been the shampoo on her?

That's genuinely one of the most common misconceptions — and the reason so many people stay stuck in this loop for months. Here's the thing: around 95% of the flea population at any one time is not on your dog at all. It's eggs, larvae and pupae sitting in your carpet, sofa and skirting boards. You can treat your dog perfectly and she'll be reinfested within 48 hours from her own living room floor. So we need to tackle both at once, and you need a product with lasting residual protection on her — not a shampoo that rinses straight off.

For your Shih Tzu, I'd go with Frontline Plus Spot On for Small Dogs — it's specifically dosed for dogs up to 10 kg, so it's right for her weight. You apply a single pipette to the skin at the back of her neck once a month. The key difference from shampoo is that it spreads across her entire skin surface within 24 hours and keeps killing adult fleas and ticks for a full four weeks, plus it contains an insect growth regulator that stops any eggs laid on her from hatching. It's been around for decades, it's well-tolerated by small breeds including Shih Tzus, and it doesn't wash off with normal bathing after the first 48 hours. At the same time — and this part is just as important — you need a household spray like Indorex Defence Household Flea Spray for the carpet and sofa. One can treats the whole house and keeps working for up to 12 months. Do both this week and you should see the infestation collapse within two to three weeks as the hatch cycle breaks down.

Good question — don't bathe her immediately before applying it. You actually want some of her natural skin oils present, because the spot on travels across her coat by spreading through those oils. If you bathe her the same day, you strip the oils and the product won't distribute as evenly. Give it at least 48 hours after her last bath before you apply, then keep her dry for another 48 hours after application. After that, normal bathing is fine and won't affect the protection. One more thing worth knowing: you might see a small increase in flea activity in the first week as larvae hatch out of the carpet before the Indorex takes full effect — that's normal, and it settles down. You haven't gone backwards; it's just the existing eggs working their way through.