Acute diarrhoea in dogs: probiotics and more

What is acute diarrhoea in the dog?

Acute diarrhoea is a sudden onset of soft or watery faeces that typically lasts less than two weeks. Common causes include dietary changes, stress, a mild infection or eating something unsuitable. In an otherwise healthy adult dog, it often resolves spontaneously. However, diarrhoea can also indicate a more serious underlying condition — see the red flags at the bottom of this page.

Additional options: what does the evidence say?

Probiotics — grade B (moderate evidence)

Two randomised, double-blind, placebo-controlled studies form the core of the available evidence.

• Shmalberg et al. (2019) compared a multi-strain probiotic with both metronidazole and placebo in dogs with acute diarrhoea [3]. Both active treatments led to faster recovery than placebo; there was no statistically significant difference between the probiotic and metronidazole.
• Nixon et al. (2019) tested a commercial probiotic paste in dogs with acute diarrhoea [4]. The treated group showed a significantly shorter duration of illness compared with placebo.

Note: both studies are relatively small in size and use different probiotic products from each other. Which bacterial strains are most effective in which dog has not yet been sufficiently established. The results are therefore not automatically applicable to any random probiotic product on the market.

Slippery elm (Ulmus rubra, red elm) — grade D (insufficient evidence)

Slippery elm is traditionally used as a demulcent for digestive complaints. The inner bark contains mucilaginous substances that are said to protect the gastric mucosa [1]. Anecdotal descriptions and a narrative review describe use in dogs and cats [2], but controlled clinical research in animals is completely lacking. Based on the current evidence, no conclusions can be drawn regarding efficacy in dogs.

Easily digestible diet and rest

A temporary easily digestible diet — typically recommended for mild acute diarrhoea — is safe and widely applied in clinical practice. Specific scientific evidence in dogs is limited, but the principle aligns with the physiology of the recovering gastrointestinal tract.

Additional is not a replacement

Probiotics and other additional measures can play a supportive role in certain situations, but are not a replacement for veterinary diagnosis or treatment. A veterinary surgeon assesses the cause, rules out dangerous conditions and can initiate targeted treatment if necessary. In case of doubt, in young puppies, older dogs or animals with other health problems, the rule applies: do not adopt a wait-and-see approach.

Comparison at a glance