Can acute hemorrhagic diarrhea spread to other pets?

Whether it is contagious depends on the underlying cause (e.g. bacterial or viral). If you have multiple pets at home, seek veterinary care promptly and follow your vet's advice on isolation and environmental cleaning.

What can I do at home to care for a pet with diarrhea in the short term?

In the short term, monitor your pet's alertness, water intake, and bowel movements and document with photos. However, if you notice bloody stools, persistent vomiting, or signs of dehydration, seek veterinary care without delay to avoid worsening the condition.

What tests are needed to identify the cause of the bleeding?

Common tests include blood biochemistry, a complete blood count, faecal examination, abdominal X-rays, and ultrasound. Depending on findings, PCR testing or bacterial culture may also be recommended — your vet will advise based on the clinical picture.

Is a follow-up visit needed after symptoms improve?

Yes, follow-up visits are recommended as advised by your vet to recheck blood values and clinical status, confirming that dehydration, infection, or anaemia have fully resolved and reducing the risk of complications.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Acute Hemorrhagic Diarrhea in Dogs & Cats: Symptoms, Diagnosis & Treatment [2025]

Acute hemorrhagic diarrhea syndrome (AHDS) is a sudden-onset condition causing bloody stools and vomiting with rapid dehydration. Most common in small-breed dogs. Emergency IV fluids and supportive care are typically needed, and most pets recover within 2–3 days.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap editorial team

Sources: WSAVA, ISFM, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate veterinary care (emergency)

•Persistent large amounts of bright red blood in the stool with frequent bowel movements
•Severe weakness, sudden inability to stand, or collapse
•Clearly poor skin elasticity with dry mucous membranes

Schedule a veterinary appointment as soon as possible (within 24-72 hours)

•A small amount of bloody stool, but still alert and able to move around
•Repeated vomiting several times, but still able to drink small amounts of water
•Clearly decreased appetite for more than 24 hours

01What Symptoms Should You Watch For?

Acute hemorrhagic diarrhea typically has a sudden onset and can progress rapidly. Key warning signs involve changes in alertness and stool consistency — watch closely for signs of bleeding and dehydration.

Lethargy, noticeably reduced activity, or drowsiness
Weakness and difficulty standing or walking
Markedly reduced appetite or refusal to eat
Repeated vomiting, occasionally with blood or dark material
Increased frequency of diarrhoea, passing mucus or bloody stools
Elevated body temperature or feeling warm to the touch (possible fever)
If bloody stools appear, arrange a veterinary visit as soon as possible

Seek emergency care immediately if you notice the following symptoms:

⚠️ Profuse fresh blood in stools with frequent defecation
⚠️ Severe weakness with sudden inability to stand or collapse
⚠️ Markedly poor skin turgor and dry mucous membranes

02How to Assess the Situation at Home: Key Observations and Emergency Criteria

Tracking these details at home helps your vet quickly assess the situation and arrange the right tests.

Note when changes in alertness and energy levels began and how they have progressed
Take photos or videos of vomit or stools on your phone to show the vet
Record the number of vomiting episodes and describe the colour and consistency of the material
Track the number of bowel movements, colour, presence of mucus or fresh blood, and approximate volume
Measure and record any changes in body temperature (if you can do so safely)
Write down all foods eaten and any potential exposures or foreign objects in the past 24 hours
If you notice bloody stools, take a photo and arrange a vet appointment promptly

03How Does the Vet Make a Diagnosis? Common Tests and Examinations

After a physical examination, your vet will use blood tests and imaging to assess dehydration, infection, and other potential causes.

Blood biochemistry panel

assesses organ function, electrolytes, and degree of dehydration

Complete blood count (CBC)

checks for anaemia, infection, or inflammatory markers

Abdominal X-rays

evaluates intestinal gas patterns, obstruction, or foreign bodies

Abdominal ultrasound

examines intestinal wall thickness, abdominal cavity, and organ status

Faecal examination (microscopy/bacterial culture) and PCR

identifies pathogens and parasites

04What Treatment and Care Are Needed? Medications, Diet, and Home Care Guide

Treatment focuses on stabilising the patient and providing supportive care. Follow-up monitoring of clinical improvement and lab values is essential after discharge, with referral or additional treatment arranged if needed.

Intravenous fluid therapy to correct dehydration and stabilise electrolytes
Antibiotics or other targeted medications considered based on test results and clinical response
Anti-emetics, pain relief, and other supportive medications to improve comfort
Severe anaemia may require blood transfusion or further interventions
Schedule follow-up appointments after discharge to monitor blood values and symptom progression
If symptoms do not improve or worsen, referral to a specialist or advanced imaging facility is recommended

05What Should You Prepare Before the Vet Visit? Key Information to Help Your Vet Act Quickly

Take photos or videos of vomit and stools to share with the vet

Note the time symptoms started, the order they appeared, and how they have changed

List all food, treats, and potential exposures in the past 24 hours (e.g. plants, rubbish)

Bring any current medications, supplements, and vaccination records

If travelling, secure your pet in a sturdy carrier or use a calming wrap

Call ahead to book an appointment and describe the symptoms and urgency so the clinic can prepare

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.