Starting a probiotic powder for a dog with a sensitive stomach: the 7-day routine we use with Merlo

If your dog has what you would call a sensitive stomach, you have probably already read our guide to choosing a probiotic powder in the UK. This article is the next step: what to actually do in the first week once the tub arrives. It is the routine I use at home with Merlo, our Cavapoo, and it is deliberately slow, because the most common reason a powder “does not suit” a dog is that the full serving went in on day one.

A quick word on language before we start. “Sensitive stomach” here means everyday owner language for a dog who is bright, eating and otherwise well but seems to have a delicate tummy, for example softer stools after a food change, a busy weekend or a scavenged treat. It is not a diagnosis. Petdentist® Probiotic Powder is a complementary feed that supports normal digestion in healthy dogs and cats. It does not diagnose, treat, cure or prevent any disease. If your dog has persistent loose stools, blood in the stool, vomiting, lethargy or pain, that is a vet appointment, not a tub of powder.

Before day one: three things to check

• Your dog is well. Start a new feed when things are calm, not in the middle of an upset. If your dog is on medication or a clinical diet, ask your vet first.
• You know the serving. The 3 g scoop is in the tub. Dogs up to 7 kg: half a scoop. 7 to 17 kg: one scoop. 18 to 40 kg: two scoops. Over 40 kg: two to three scoops. Cats of any size: one scoop. The full table is on the product page.
• Nothing else is changing. Do not switch food, add a new treat and start a probiotic in the same week. If the stools change you will not know why.

The 7-day routine

Days 1 to 2: half the serving, once a day

Give half of your dog's daily serving with the main meal. For Merlo (about 9 kg) that is half a scoop. Mix it into wet food, or add a splash of warm water to kibble so the powder sticks instead of sitting in the bottom of the bowl. Most dogs do not notice it; it is a fine, mild powder with no strong smell.

Days 3 to 4: still half, watch the bowl and the garden

Keep the half serving. This is the “nothing happens” stage and that is the point. You are checking that your dog eats normally and that stools stay about the same. A slightly softer or slightly firmer stool in the first few days is common with any change to the diet and usually settles on its own.

Days 5 to 7: move up to the full serving

Go to the full daily serving for your dog's weight. Larger dogs can split it between two meals if that is easier. Keep fresh water available all the time, as you should anyway.

From week two: make it boring

The best routine is the one nobody thinks about. Keep the tub next to the dog food, scoop in the tub, same meal every day. A 90 g tub is 30 servings of 3 g, so a small dog on half a scoop gets about two months from a tub and a Labrador on two scoops gets about two weeks. That difference matters for the “never run out” part below.

Five mixing tricks for fussy dogs

1. Warm water on kibble. A tablespoon is enough; the powder clings to the coating.
2. Stir into a spoon of wet food and put it on top of the dry food, so the first mouthful is the one with the powder in.
3. Mix into a lick mat with a little plain wet food if your dog bolts meals.
4. Stir into drinking water is allowed on the label, but only if your dog reliably finishes the bowl; otherwise you cannot tell how much went in.
5. Do not hide it in a high-value treat such as cheese or peanut butter every day. You are adding calories and a new variable to a sensitive tummy.

What is normal, and when to stop and ring the vet

Normal in week one: eating as usual, bright and playful, stools roughly the same as before, perhaps slightly softer or firmer for a day or two.

Stop and speak to your vet if: stools are loose for more than a couple of days, there is any blood or mucus, your dog vomits, goes off food, seems lethargic or in pain, or anything else worries you. A complementary feed is for well pets. It is never the answer to a dog who is unwell, and a vet may want to see your dog before you add anything to the diet again.

Keeping the routine going: never run out

The pattern we see most often is this: the first tub goes well, the dog is settled, and then the tub runs out on a Tuesday and nobody reorders until the following week. The routine breaks exactly when it was becoming a habit.

Two ways round it. The first is simply to buy three or six tubs at once, which is also cheaper per tub. The second, and the one most of our customers with one dog choose, is Subscribe & Save: pick the 90 g powder on the product page, choose a delivery every 4 or 8 weeks, and it arrives from Northampton before the tub is empty, at 15% off every delivery. There is no minimum term and no cancellation fee; you can skip a delivery, change the frequency, pause or cancel from your account at any time. Every 4 weeks suits a dog on one scoop a day; a small dog on half a scoop can stretch to every 8 weeks.

Orders of £35 or more get free UK delivery (Royal Mail Tracked 48); under £35 it is £5.95. We deliver to UK addresses only.

Frequently asked questions

Can I start the full serving straight away?

You can, and many dogs are fine, but we recommend half the serving for the first three or four days, especially for a dog you already describe as having a sensitive stomach. It costs you nothing but a few days.

Does the powder need to go in the fridge?

No. Store it below 30°C in a cool, dry place with the lid closed.

Can my cat have the same tub?

Yes. The 90 g powder is a complementary feed for dogs and cats; cats of any size get one scoop a day. Our 500 g High Fibre powder is for dogs only.

How long until I notice a difference?

Think of it as part of the normal diet rather than something with a result to wait for. It is a daily feed that supports normal digestion, not a treatment, so there is nothing to “kick in”. If your dog is unwell, see your vet.

Can I give it with other Petdentist products?

Yes. Brushing with a pet toothpaste, dental play and the probiotic sit alongside each other in the daily routine. The powder is for digestion only and makes no dental claims.

What if I miss a day?

Just carry on the next day at the normal serving. Do not double up.

About the author

Dr Deepak Songra BDS is a dental surgeon registered with the General Dental Council (GDC 68552) and the founder of Petdentist®, part of the PetdentistCare™ platform. He is not a veterinary surgeon. This article is educational information about a non-medicinal complementary feed and is not veterinary advice. If you are worried about your pet's health, please consult your vet.