(BPT) - Diarrhea in pets has a way of showing up at the worst possible time, leaving pet parents scrambling for answers and unsure whether to wait it out or call the vet. It's one of the most common reasons pets feel under the weather, and it's not always obvious what will actually help.
Ahead of National Cat & Dog Gut Health Awareness Day on September 21, Purina Veterinary Nutritionist Martha Cline, DVM, DACVIM, shares some tips on what pet parents should know about easing their pet's tummy troubles as soon as possible and keeping their gut healthy so it's less likely to happen again.
What's causing your pet's diarrhea?
Diarrhea is a common complaint in both dogs and cats, with a wide range of potential causes, but there are two common culprits: diet and stress. A sudden food switch, a change in routine, new construction noise, or even a new pet or baby in the house can all play a role.
3 ways to help your pet feel better
1. Slowly introduce new foods
"If you've recently introduced a new food, it might not be sitting well with your cat or dog," said Dr. Cline. "A slower introduction, or mixing it with their usual food, can help their stomach adjust." If your pet's diet has not changed, a temporary switch to a highly digestible or fiber-enhanced diet may help. Confirm with your vet before making any changes.
2. Provide a quiet environment
If things have been chaotic at home lately, give your pet a way to reset. For cats, that could be a place to escape the hustle and bustle, like a cozy hideaway or a special box of their own. Dogs tend to do best when sticking closely to their routine. Extra one-on-one attention and a chew toy can also help burn off nervous energy.
3. Consider a supplement
For extra support, skip the human medicine cabinet and stick to supplements designed specifically for pets.
"The best supplements for pets are created in collaboration with veterinarians with expertise in health and nutrition," said Dr. Cline.
FortiFlora Diarrhea Response Kit for pets (dogs; cats) with occasional diarrhea from Pro Plan Veterinary Supplements is one option. Developed by Purina scientists, it pairs FortiFlora Response stick packs for short-term use to help firm loose stools with FortiFlora sachets — the No. 1 vet-recommended probiotic brand to support digestive health*, no prescription required. FortiFlora Response stick packs contain kaolin and pectin to soothe the GI tract during times of loose stool, and come in an easy-to-mix, liver-flavored powder you can pour right into your pet's bowl.
"Diarrhea can be difficult for pets and pet parents, but having a plan takes a lot of stress out of it," said Dr. Cline. "Keeping something like the FortiFlora Diarrhea Response Kit on hand means you're ready no matter when it strikes."
Additional signs to watch for
It helps to note how long the diarrhea lasts and any other symptoms that show up. These details can point to whether there's a bigger issue.
"If you notice vomiting, changes in appetite or energy, or diarrhea that isn't improving or worsens within 72 hours, it's time to call your veterinarian," added Dr. Cline.

The best supplements for pets are created in collaboration with veterinarians with expertise in health and nutrition.

How to prep for your vet visit
If you do need to see your vet, a little prep goes a long way:
- Take note of the details. Frequency, whether there's blood or mucus, and any straining are all useful to share. The Fecal Scoring Chart from Purina Institute is a helpful tool for describing what you're seeing.
- Collect a sample so your vet can screen for parasites, another common cause of diarrhea.
- Offer plenty of fresh water to help prevent dehydration.
How to support your pet's gut health long-term
An episode of diarrhea can be handled in the moment, but the goal is to help your pet avoid another round of it. That's where the FortiFlora sachets come in: daily use helps keep your pet's digestive and immune systems on track. They contain Enterococcus lactis SF68, a safe, effective single-strain probiotic that helps promote healthy digestive and immune systems, backed by over 20 years of research.
So next time your pet's stomach acts up, there's no more debating what to do or searching for answers at midnight. With a plan already in place, pet parents can skip the stress and get straight to helping their pet feel better.
*Online survey among all qualified U.S. veterinarians who indicated the brand as one of 1-3 brands recommended, Q4 2025.
