In this article

1. Some signs mean calling immediately
2. Puppies, older dogs and medicines need earlier advice
3. Home monitoring needs a clear boundary
4. Common does not tell you what this episode needs
5. Why the vet may not prescribe antibiotics
6. Use the call to decide together

A puddle by the back door, an interrupted night and a dog who does not seem quite themselves can make the next decision feel difficult. Many short bouts of diarrhoea are mild, but blood, vomiting, low energy, pain or an underlying health problem are reasons to contact your vet promptly¹.

Start with the dog, rather than trying to name the illness. Are they alert? Are they drinking? What else has changed? You do not need to decide whether this is a stomach bug, something eaten or another condition before describing it to the practice.

Some signs mean calling immediately

PDSA advises immediate contact for continuous retching with little or nothing produced, particularly with a bloated abdomen: this can indicate gastric dilatation volvulus, or GDV. Continuous vomiting, blood in vomit, collapse, disorientation or signs of dehydration also need prompt veterinary assessment².

Animal Trust lists suspected poisoning or a swallowed foreign object among emergencies associated with vomiting or diarrhoea. Tell the practice about a missing toy, raided bin or possible toxin even if you did not see it swallowed. Do not wait for the story to become certain before asking for help³.

What you notice	What to tell the practice
Blood, marked weakness or a painful abdomen	Describe it at the start of the call1.
Unproductive retching or a swollen abdomen	Say that the dog may need emergency assessment2.
Possible poison or swallowed object	Explain what may be missing and when3.

Stay with the description you can give. “He has tried to be sick several times but nothing comes up” is more useful than a guess at the diagnosis. If another person can fetch packaging or look for the missing object, one of you can make the call immediately.

Puppies, older dogs and medicines need earlier advice

PDSA advises contacting the vet sooner for very young or old dogs, underlying illness or medication use, particularly anti-inflammatory medicines known as NSAIDs. Blood or mucus, severe watery diarrhoea, reduced appetite, lethargy and abdominal pain also matter. Mild-looking stools do not cancel out those other concerns¹.

Give the team the names of current medicines and when they were last given. Ask how the illness affects the next planned administration, rather than improvising a change yourself. Mention any recent treatment as well as long-term prescriptions, and say if another household member may have offered something.

Animal Trust advises against human medicines for diarrhoea. It also warns against rich or fatty foods, dairy products and table scraps. A medicine that seems familiar from your own cupboard can be the wrong choice for a dog, so ask the practice what is appropriate for this individual³.

Have the dog's age, health history and a contact number ready. If cost or transport affects what you can manage, explain that during the call. The practical aim is to reach an agreed next step, including where to go and how quickly if an examination is needed.

Home monitoring needs a clear boundary

PDSA's home-care advice is restricted to mild diarrhoea lasting less than 24 hours in a dog who otherwise seems well. Contact the practice if symptoms continue beyond that, if anything worsens or if another sign develops. The 24-hour point is not a reason to delay when red flags are already present¹.

For a dog who has vomited once and otherwise seems well, PDSA advises fresh water, encouraging small frequent drinks, rest and small portions of an easily digested diet. Continued vomiting or deterioration changes the plan. If water repeatedly comes back up, tell the veterinary team rather than relying on more home care².

Animal Trust recommends a highly digestible, low-fat diet for acute diarrhoea, with familiar protein ingredients. Ask your vet which feeding plan suits your dog, especially with other medical needs. Avoid a succession of new foods and remedies while trying to work out what settles the stomach³.

This guide does not set a fasting timetable. Feeding advice needs to fit age, health, the symptoms and what the practice has already recommended. Write the agreed plan down, including when to give an update, so another carer can follow it without piecing together several different webpages.

Keep the record simple: time, vomiting or stool episode, appetite, drinking and how the dog behaves between episodes. Add what you actually saw, rather than rating everything “better” or “worse.” If the practice asks for a sample, ask how they would like it collected and brought in.

Common does not tell you what this episode needs

A 2025 VetCompass study estimated that around one in twelve dogs under UK veterinary care had an incident episode of uncomplicated acute diarrhoea recorded during 2019. The researchers examined 1,835 confirmed cases from a much larger practice-record population. They excluded diarrhoea recorded within other formal diagnoses such as poisoning or systemic disease⁴.

Just over 80% had only one physical veterinary visit for the first episode analysed. That is reassuring about the general pattern following care, but absence of another visit is not the same as independently confirming recovery at home. The records also showed vomiting, appetite change and lethargy were common accompanying signs⁴.

The findings reflect 2019 records and the information clinicians documented. They cannot predict how quickly your dog will recover or safely classify a new case without assessment. A common presentation still deserves individual decisions about examination, fluids, symptom relief and follow-up⁴.

Why the vet may not prescribe antibiotics

A separate UK study used 2019 clinical records to emulate treatment trials. Among selected dogs with uncomplicated acute diarrhoea, it found no significant improvement in its resolution measure with an antibiotic prescription at the first visit. That measure was based on no return visit for ongoing diarrhoea within 30 days⁵.

This was an observational analysis using statistical adjustment, rather than random allocation of treatment. Unmeasured differences could remain. Dogs requiring hospitalisation or intravenous fluids at presentation, and several specific illnesses, were excluded, so the findings should not be extended to every seriously ill dog with diarrhoea⁵.

The study also found no significant improvement in that outcome with prescribed gastrointestinal nutraceuticals. Those products varied, and the result cannot establish that every individual probiotic is ineffective. It supports asking what a proposed treatment is expected to do, while keeping decisions with the vet examining the dog⁵.

ENOVAT's veterinary guidelines recommend against routine antimicrobials for mild and moderate acute diarrhoea, including many cases with blood, while recognising exceptions and a role in severe systemic illness. These categories depend on clinical assessment and response to care. They are not instructions for an owner to grade illness or refuse a prescription⁶.

The guidelines make no recommendation for or against probiotics because the trade-offs are closely balanced. Ask about likely benefits, uncertainties and the review plan. A consultation can provide useful care without an antibiotic, and a dog with severe disease may need treatment that differs substantially from the usual mild case⁶.

Use the call to decide together

A 2026 UK study gave 1,772 owners short clinical scenarios and compared their urgency judgements with a veterinary panel. Across 5,316 responses, owners judged care less urgent in around 28%. Gastrointestinal foreign bodies were among the conditions identified least accurately. Recognising the likely condition and judging urgency were different tasks⁷.

These were hypothetical vignettes, with self-selected participants and limited case context, rather than observations of real emergencies. The study supports making professional triage easier to use; it does not mean owners should diagnose more diseases before calling. A clear description can start the conversation without the correct label⁷.

Save those answers beside your notes. If the dog changes, call again with the new information. The plan should leave you with something more useful than “wait and see”: a next step, a time to review and a clear route to help.

Sources and further reading7 sources

The small numbers in the article link to the source behind each fact. Sources open on their own websites.

1. Dog DiarrhoeaPDSA
2. Vomiting in dogsPDSA
3. Symptom: Diarrhoea – Why does my pet have diarrhoea?Animal Trust
4. Epidemiology and clinical management of acute diarrhoea in dogs under primary veterinary care in the UKPLOS ONE
5. Target trial emulation: Do antimicrobials or gastrointestinal nutraceuticals prescribed at first presentation for acute diarrhoea …PLOS ONE
6. ENOVAT GUIDELINES FOR ANTIMICROBIAL USE IN CANINE ACUTE DIARRHEAWSAVA Therapeutics Committee / ENOVAT
7. To see or not to see the vet: A vignette-based study of decision-making by UK dog owners regarding seeking veterinary care …PLOS ONE