Diarrhea in dogs: what to feed, how long it lasts and when to see a vet

Acute diarrhea is diagnosed in roughly one in twelve dogs per year: 8.18 % in a sample of 2.25 million dogs in the UK (O'Neill et al., 2025). In 83.6 % of cases it is mild, and in 95.4 % of the dogs that were followed up, signs resolved within 10 days (Singleton et al., 2019, 3189 cases). Vets advised a diet change in 69.8 % of cases and fasting in only 19.1 %. An adult, alert dog that is drinking and not vomiting can eat a bland diet from day one.

Key points

• Acute diarrhea is diagnosed in 8.18 % of dogs per year, 83.6 % of episodes are mild, and 37 % reach a vet (O'Neill 2025; Singleton 2019; Pugh 2017).
• Vets advised a diet change in 69.8 % of cases and fasting in 19.1 %; antibiotics were not associated with recovery (Singleton 2019).
• Chicken and rice 1:2 provides 6 % of the FEDIAF calcium minimum and a Ca:P of 0.13:1 against a minimum of 1:1, so it is food for a few days.
• A 28 kg Labrador needs 995 g of this mix a day versus 343 g of dry food at 397 kcal/100 g.
• Severity is judged by the dog's condition, not by how often it has diarrhea: lethargy, dehydration, vomiting, blood, a temperature above 39.3 °C and diarrhea in a puppy mean an exam right away (ENOVAT 2024).

Should you starve a dog with diarrhea?

Fasting is not necessary for acute diarrhea: in 3189 cases at 179 UK clinics, vets advised a diet change in 69.8 % of cases and fasting in only 19.1 % (Singleton et al., 2019).

In the same study, dietary advice with nutraceuticals and no drugs was associated with recovery (odds ratio 2.8; 95 % CI 1.3–6.1), while drugs, including antibiotics, were not associated with recovery.

The day of fasting comes from tradition. A 2020 review calls 24–48 hours of “bowel rest” a traditionally accepted approach that has an alternative: feeding from the first days (Candellone et al., 2020).

Even in severe parvoviral enteritis, early feeding from hour 12 shortened the time to normal condition, appetite and stools by about a day compared with fasting (Mohr et al., 2003, 30 dogs). Fresh water should always be available (NRC, 2006).

What to feed a dog with diarrhea and how much?

A highly digestible diet is food with low residue and moderate fat, below 14 % of dry matter: either a ready-made gastrointestinal diet or a temporary home-cooked diet (Candellone et al., 2020).

The most common home option, boiled chicken breast with boiled rice 1:2 by weight, provides only 137 kcal per 100 g (USDA FoodData Central), so the dog needs a lot of it.

Our own calculation based on USDA FoodData Central; amount per the site calculator's method (70 × kg^0.75 × 1.6). The RER row is a “less than usual” guide: there is no primary source on how much to give in the first days. How the amount is calculated: see the article on food amount by weight.

It is better to give small portions. Use medicines from your home first-aid kit only after a vet has examined the dog; the ENOVAT guideline makes no recommendation for or against probiotics (Jessen et al., 2024).

Can you keep a dog on chicken and rice for a week?

A week on chicken and rice means a week with almost no calcium: the 1:2 mix provides 0.080 g per 1000 kcal, which is 6 % of the FEDIAF 2025 minimum (1.25 g), and a calcium to phosphorus ratio of 0.13:1 against a minimum of 1:1.

Our own calculation based on USDA FoodData Central (FDC 171478 breast, FDC 168878 rice) and FEDIAF 2025, tables III-3a and III-3b.

For two or three days of bland food this imbalance has no effect: an adult dog's reserves exceed its daily requirement. The myth breaks down over weeks, when the same mix becomes a diet without calcium.

How long does diarrhea last in dogs?

Acute diarrhea is diarrhea that starts suddenly and lasts up to a few days; if gastrointestinal signs persist for more than three weeks, it is a reason to consider a chronic problem (Tamura, 2025).

A typical episode lasts 1–3 days. In a cohort of 6084 Labradors, owners reported 2687 episodes of diarrhea, and most lasted one to three days (Pugh et al., 2017). Only 37 % of episodes reach a vet, and when diarrhea lasted two days or more, 66 % went to a vet.

On a highly digestible food, the median time to remission in 59 dogs with acute non-infectious colitis was 5 days, with a range of 4–10 (Rudinsky et al., 2022). The ENOVAT guideline adds that most cases resolve within a week.

The “48 hours” threshold from Ukrainian articles does not appear in primary sources: the two days in Pugh's data describe owner behavior, not a recommendation.

When is diarrhea in dogs caused by food?

Among recorded causes of acute diarrhea, scavenging or eating “the wrong thing” comes first at 9.54 %, a change of food accounts for 4.58 %, and in 40.11 % of cases no cause was recorded at all (O'Neill et al., 2025).

In a case-control study, scavenging or a recent diet change increased the odds of diarrhea 3.5 times, a home-cooked diet 4 times, and a stay at a boarding kennel 9.5 times (Stavisky et al., 2011). None of the pathogens tested remained significant in the final model.

How to bring a dog back to its usual food after diarrhea?

Bring back the usual food gradually, because a sudden diet change is itself a risk factor for diarrhea, with odds of 3.5 (Stavisky et al., 2011). The procedure is the same as when changing food and is covered separately: how to switch a dog to a new food in 7 days.

DELICATE is a manufacturer of dry food for adult dogs from Dnipro: 397 kcal per 100 g (calculated per NRC 2006) and, per the label, 32 % crude protein, calcium 1.4 % and phosphorus 1.1 %; a 10 kg bag costs UAH 1,188 with delivery. For the 28 kg Labrador in the example, that is 343 g a day, about UAH 41 a day, and a bag lasts about 29 days. This food is not sold as a diet for diarrhea: therapeutic gastrointestinal diets are made separately. It suits a healthy adult dog returning to its normal food and does not suit a dog on a vet-prescribed diet.
See the food — UAH 1,188

When should you take your dog to the vet right away?

The severity of acute diarrhea is judged by the dog's condition. The ENOVAT guideline (16 experts, GRADE method) puts it this way: “Categorization is not based on volume or frequency of diarrhea” (Jessen et al., The Veterinary Journal, 2024).

The mild form is when the dog is bright, active and responsive as usual, with no dehydration and no fever; the guideline allows such a dog to be treated at home. Don't wait if any of the following apply:

• diarrhea in a puppy, especially before vaccinations are complete: parvovirus mainly affects puppies aged 4–12 weeks;
• the dog is lethargic, depressed or not responding as usual;
• it is not drinking or shows signs of dehydration;
• vomiting that does not stop;
• bloating or abdominal pain that is getting worse;
• a temperature above 39.3 °C;
• blood in the stool;
• the dog has eaten something toxic to dogs;
• diarrhea keeps coming back;
• several animals in the household or people in the family have similar symptoms;
• it does not resolve within a week; more than three weeks means a chronic problem.

What to do with the food bowl these days?

If your dog is alert, drinking, not vomiting and the diarrhea started today, keep water available at all times and give bland food in small portions. For a 28 kg Labrador, that is about 995 g of chicken and rice 1:2, i.e. 332 g of chicken and 663 g of rice.

• If your dog weighs a different amount, take its daily amount from the portion calculator and divide by 1.37 to get the grams of the 1:2 mix.
• If there is no improvement by day three, see a vet without waiting a week.
• If the diarrhea has passed, bring back the usual food gradually using the switching plan, not in one bowl.
• If any item from the list above appears, see a vet right away.

Questions and answers