How can I take my pet's temperature at home?

Use a pet-specific rectal thermometer and record the time and reading. If you are unsure how to do this safely, call your vet for guidance before attempting it.

When should I take my pet to the emergency vet immediately?

Seek emergency care immediately if your pet has severe breathing difficulty, repeated seizures or loss of consciousness, or gums that are pale white or blue/purple.

What initial tests will the vet run at the clinic?

Standard initial tests include a complete blood count (CBC), blood biochemistry, urinalysis, and chest and abdominal imaging. Culture or additional imaging may also be arranged if needed.

Can I give my pet human fever-reducing medication at home?

Never give your pet human medications or adjust dosages on your own. If the fever persists or worsens, contact your vet or arrange an appointment.

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

Dog and Cat Fever Guide: Lethargy, Diagnosis & Home Care [2025]

Fever is a symptom, not a disease — it may be caused by infection, inflammation, or tumours. Identifying the underlying cause is essential for targeted treatment. Fever of unknown origin may require extensive diagnostic workup.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: AVMA, WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate emergency care

•Persistent difficulty breathing with heavy open-mouth panting
•Repeated seizures, confusion, or unresponsive loss of consciousness
•Gums or lips clearly pale or turning purple/blue

Schedule a clinic visit soon (within 24–72 hours)

•Elevated body temperature persisting for multiple days without noticeable improvement
•Significantly reduced appetite and decreased water intake lasting more than one day
•Markedly low activity level with continued lethargy and poor alertness

01What Symptoms Indicate a Problem?

Fever often affects a pet's energy and physical function. Behavioural changes and physiological indicators are the key things to watch.

Lethargy and noticeably reduced activity levels
Reduced appetite or complete refusal to eat
Persistent or intermittent elevated body temperature
Faster breathing or visible panting
Rapid heart rate or noticeably elevated pulse
Dry mouth and reduced skin elasticity indicating dehydration

Seek emergency care immediately if you notice the following symptoms:

⚠️ Severe difficulty breathing with continuous open-mouth panting
⚠️ Repeated seizures, disorientation, or loss of consciousness
⚠️ Gums or lips turning pale white or blue/purple

02How to Monitor at Home: Key Observations and When to Seek Emergency Care

Observing and recording key information at home helps your vet quickly assess disease progression and plan the appropriate tests.

Record the onset time and how symptoms have progressed
Take your pet's temperature at the same time each day and log the readings
Note any changes in food and water intake
Film short videos of your pet's activity level and breathing on your phone
Monitor urination and defecation frequency and any changes in colour

03How Will the Vet Diagnose the Problem? Common Diagnostic Tests

At the clinic, the vet will typically use blood tests and imaging as the primary workup, combined with urinalysis and, if needed, culture or tissue sampling to identify the cause of the fever.

Complete blood count (CBC)

assess for signs of infection or anaemia

Blood biochemistry panel

evaluate liver, kidney, and metabolic function

Urinalysis

detect urinary tract or metabolic issues

Chest and abdominal X-rays

check for pulmonary or abdominal abnormalities

Cardiac ultrasound or tissue culture as indicated for further investigation

04Treatment and Care After Diagnosis: Medication, Diet, and Home Management

Targeted treatment is provided based on diagnostic findings, alongside supportive care and regular follow-up to ensure full recovery.

Anti-infective or symptomatic treatment based on test results
Unstable cases may require hospitalisation for monitoring and supportive care
Immune-mediated or inflammatory conditions may require specialist referral
Regular follow-up visits after discharge, including repeat blood tests or imaging
Persistent or recurrent fever warrants further specialist investigation

05What to Prepare Before the Vet Visit: Helping Your Vet Identify the Cause Quickly

Write down the onset time and a detailed record of how symptoms developed

List recent changes in appetite, water intake, and elimination habits

Bring a list of any current or recently used medications or supplements

Film short clips showing your pet's activity, breathing, and alertness

Bring any previous relevant test reports or imaging results

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.