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Nonsteroidal Anti-Inflammatory Drug (NSAID) / Antiplatelet Agent · For Cats

Bayer Aspirin dosage reference for cats (Aspirin (Acetylsalicylic Acid))

This page's standard weight-based reference is 8 mg per kg (3.63 mg per lb), with Every 48-72 hours ONLY (NOT daily) recorded as the reference frequency. Use the calculator to see the arithmetic for your cat's weight, then confirm the indication, product, and actual dose with a veterinarian.

Onset
30-60 minutes
Duration
48-72 hours in cats (due to slow metabolism)
Class
Nonsteroidal Anti-Inflammatory Drug (NSAID) / Antiplatelet Agent

Weight-based calculator estimate from the references listed on this page. This page has not been independently DVM-reviewed — see our methodology .

This information is for educational purposes only. Always consult your veterinarian before giving medication to your pet. Do not use this calculator for emergencies, overdoses, pregnancy, very young animals, very old animals, pets with liver/kidney disease, or pets taking multiple medications.

Each medication page lists the references recorded for its data. The calculator math and editorial presentation are maintained by PetDosageChart; a page is independently DVM-reviewed only when a named reviewer byline appears. See our methodology and limitations.

Aspirin (Acetylsalicylic Acid) (often known by brand names such as Bayer Aspirin, Ecotrin, and Bufferin) is a nonsteroidal anti-inflammatory drug (NSAID) / antiplatelet agent commonly used in veterinary medicine for Blood clot prevention (thromboembolism prophylaxis), Aortic thromboembolism (saddle thrombus) prevention in cats with heart disease, Anti-inflammatory use (very limited, with extreme caution), and Fever reduction (rare, other options preferred). Understanding the correct dosage, administration, and potential side effects of Aspirin (Acetylsalicylic Acid) is critical for your cat’s safety and well-being.

A typical Aspirin (Acetylsalicylic Acid) dose for cats is around 8 mg/kg Every 48-72 hours ONLY (NOT daily), within a usual range of 6-10 mg/kg. Available forms include Tablet and Baby aspirin (81 mg).

Calculator Warning: Use this only as an educational estimate. Your veterinarian may prescribe a different dose based on your pet’s condition, age, weight, other medications, and medical history.

Aspirin (Acetylsalicylic Acid) Dosage Calculator for Cats

Enter your cat’s weight below to estimate the Aspirin (Acetylsalicylic Acid) dose from the 8 mg/kg guideline. Your veterinarian may adjust it for your cat’s age, condition, and other medications, so treat the result as an educational starting point, not a prescription.

Dosage Calculator · 01

Enter your cat's weight

Quick Dosage Chart

Typical Aspirin (Acetylsalicylic Acid) amounts for common cat weights, for quick reference:

Dosage Chart · 02

Bayer Aspirin weight-based reference chart for cats

Scroll sideways to see full table

Weight Lower Reference Standard Reference Upper Reference Frequency
3 lbs (1.4 kg) 8.4 mg 11.2 mg 14.0 mg Every 48-72 hours ONLY (NOT daily)
4 lbs (1.8 kg) 10.8 mg 14.4 mg 18.0 mg Every 48-72 hours ONLY (NOT daily)
5 lbs (2.3 kg) 13.8 mg 18.4 mg 23.0 mg Every 48-72 hours ONLY (NOT daily)
6 lbs (2.7 kg) 16.2 mg 21.6 mg 27.0 mg Every 48-72 hours ONLY (NOT daily)
7 lbs (3.2 kg) 19.2 mg 25.6 mg 32.0 mg Every 48-72 hours ONLY (NOT daily)
8 lbs (3.6 kg) 21.6 mg 28.8 mg 36.0 mg Every 48-72 hours ONLY (NOT daily)
9 lbs (4.1 kg) 24.6 mg 32.8 mg 41.0 mg Every 48-72 hours ONLY (NOT daily)
10 lbs (4.5 kg) 27.0 mg 36.0 mg 45.0 mg Every 48-72 hours ONLY (NOT daily)
12 lbs (5.4 kg) 32.4 mg 43.2 mg 54.0 mg Every 48-72 hours ONLY (NOT daily)
14 lbs (6.3 kg) 37.8 mg 50.4 mg 63.0 mg (81mg tablet) Every 48-72 hours ONLY (NOT daily)
16 lbs (7.3 kg) 43.8 mg 58.4 mg 73.0 mg (81mg tablet) Every 48-72 hours ONLY (NOT daily)
18 lbs (8.2 kg) 49.2 mg 65.6 mg (81mg tablet) 82.0 mg (81mg tablet) Every 48-72 hours ONLY (NOT daily)
20 lbs (9.1 kg) 54.6 mg 72.8 mg (81mg tablet) 91.0 mg (81mg tablet) Every 48-72 hours ONLY (NOT daily)
25 lbs (11.3 kg) 67.8 mg (81mg tablet) 90.4 mg (81mg tablet) 113.0 mg Every 48-72 hours ONLY (NOT daily)

Parenthetical tablet amounts are arithmetic comparisons only. They do not account for scoring, release type, concentration, product labeling, or whether this medication is appropriate for an individual animal.

By Weight

Bayer Aspirin reference by cat weight

Choose a common weight to open its optional reference page. Use the main medication calculator for a different exact weight.

Common-weight pages are convenience views of the same educational reference, not separate medical recommendations.

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How to Give Aspirin (Acetylsalicylic Acid) to Your Cat

CRITICAL SAFETY WARNING: Cats metabolize aspirin extremely slowly. NEVER give more frequently than every 48-72 hours. Use baby aspirin (81 mg) tablets for easier dosing. The tablet can be given whole or halved, hidden in a pill pocket or a small amount of soft food. Always give with food to reduce stomach irritation. Use a pill gun to place at the back of the tongue if giving directly. Mark your calendar clearly when each dose is given to avoid accidental double-dosing. If you miss a dose, simply give the next one at the regular 48-72 hour interval—never give two doses close together.

It is generally recommended to give Aspirin (Acetylsalicylic Acid) with food to help reduce stomach upset. It may interact with Other NSAIDs (severely increased toxicity and GI bleeding), Corticosteroids (increased GI ulceration), Heparin and warfarin (increased bleeding risk), Furosemide (reduced diuretic effect), and Methotrexate (increased methotrexate toxicity).

Side Effects and Safety

Common side effects include Decreased appetite, Vomiting, Gastric irritation, and Diarrhea. More serious side effects can occur, such as Gastrointestinal ulceration and hemorrhage, Kidney failure, Liver damage (hepatotoxicity), Bone marrow suppression, and Salicylate toxicity (panting, vomiting, seizures, death).

Cautions · 12

When Bayer Aspirin should be used with caution or avoided

Some cats should not take Bayer Aspirin, or need a different dose and closer monitoring. Tell your veterinarian about your pet's full health history and every other medication or supplement they take before giving Bayer Aspirin.

  • Concurrent use of other NSAIDs or corticosteroids
  • Bleeding disorders or upcoming surgery
  • Kidney or liver disease
  • Gastrointestinal ulcers
  • Asthma
  • Dehydrated cats

Interactions · 13

Bayer Aspirin drug interactions

Bayer Aspirin can interact with other drugs. This list is not complete — always give your veterinarian a full list of your cat's medications and supplements.

Other NSAIDs (severely increased toxicity and GI bleeding)
Corticosteroids (increased GI ulceration)
Heparin and warfarin (increased bleeding risk)
Furosemide (reduced diuretic effect)
Methotrexate (increased methotrexate toxicity)

Calculator Limits · 14

When not to use this calculator

This calculator gives a general educational estimate for a healthy adult cat at a known weight. Do not rely on it in these situations — talk to your veterinarian instead:

  • In an emergency, or after accidental ingestion or a suspected overdose
  • For pregnant or nursing pets
  • For very young or very old cats
  • For pets with liver disease, kidney disease, or another chronic illness
  • For pets taking several medications at once
  • When you are not sure of your cat's current, accurate weight
  • For combination products that contain additional active ingredients

Overdose · 15

Suspected overdose: what to do

If you think your cat had too much Bayer Aspirin, or swallowed any medication by accident, act right away. Do not wait for symptoms to appear.

  • Call your veterinarian or the nearest emergency animal hospital.
  • ASPCA Animal Poison Control Center: (888) 426-4435
  • Pet Poison Helpline: (855) 764-7661

A consultation fee may apply to the poison hotlines. Have the medication packaging ready, and note how much your pet may have taken and when. Do not try to make your pet vomit unless a veterinarian tells you to.

When to Call the Vet

If your cat experiences any of the following, contact your veterinarian or an emergency clinic immediately:

Frequently Asked Questions

Frequently Asked · 07

Questions about this medication

Why can't cats take aspirin like dogs or humans?
Cats have a critical deficiency in the liver enzyme glucuronyl transferase, which is needed to metabolize aspirin (and many other drugs). This means aspirin stays in a cat's body for 48-72 hours compared to 7-8 hours in dogs and 3-4 hours in humans. If dosed at the same frequency as dogs or humans, aspirin rapidly accumulates to toxic levels in cats. This is why cats can ONLY receive aspirin every 48-72 hours, never daily.
What is the correct aspirin dose for cats?
The dose for cats is 6-10 mg/kg given every 48-72 hours (NOT every 6-8 hours as in dogs). For blood clot prevention, many vets prescribe a low-dose baby aspirin (81 mg) every 72 hours for an average cat. For anti-inflammatory purposes, 10 mg/kg every 48 hours may be used short-term. NEVER give daily aspirin to a cat. Even one extra dose can push a cat toward toxicity.
What are the signs of aspirin poisoning in cats?
Signs of aspirin toxicity in cats include rapid breathing or panting, vomiting (possibly with blood), loss of appetite, lethargy, wobbliness, fever, abdominal pain, dark or bloody stool, increased drinking and urination, and in severe cases, seizures and coma. Aspirin toxicity is a medical emergency—if you suspect your cat has received too much aspirin, seek immediate veterinary care. Treatment includes decontamination, IV fluids, and supportive care.
Is aspirin used to prevent blood clots in cats with heart disease?
Yes, low-dose aspirin (81 mg every 72 hours for an average cat) has traditionally been used to reduce the risk of arterial thromboembolism in cats with hypertrophic cardiomyopathy (HCM). However, clopidogrel (Plavix) has largely replaced aspirin for this purpose, as studies have shown it to be more effective. Some cardiologists use both drugs together. Always follow your veterinary cardiologist's recommendations.
Can I give my cat baby aspirin?
Baby aspirin (81 mg) is the most commonly used aspirin formulation for cats because the dose is more manageable. However, even baby aspirin should ONLY be given under direct veterinary supervision and typically no more frequently than every 48-72 hours. An 81 mg baby aspirin may be appropriate for a 4-5 kg cat at the anti-platelet dose, but this should be confirmed by your vet. Never give aspirin to your cat on your own.

Use This Guide Safely · 08

What weight alone cannot tell you

The calculator performs one narrow job: it multiplies your cat's weight by the lower, standard, and upper mg/kg values recorded for Bayer Aspirin. It cannot decide whether this drug, indication, formulation, or schedule is appropriate for an individual animal.

Context in this medication record

Commonly listed uses
Blood clot prevention (thromboembolism prophylaxis), Aortic thromboembolism (saddle thrombus) prevention in cats with heart disease, Anti-inflammatory use (very limited, with extreme caution), Fever reduction (rare, other options preferred)
Recorded forms
Tablet, Baby aspirin (81 mg)
Reference timing
Every 48-72 hours ONLY (NOT daily); onset 30-60 minutes; duration 48-72 hours in cats (due to slow metabolism)

Individual checks a calculator cannot perform

  • Confirm the diagnosis and the reason this medication is being considered.
  • Match the exact product, concentration, route, and whether a tablet may be split.
  • Account for age, pregnancy, organ function, genetics, allergies, and prior reactions.
  • Review every prescription, over-the-counter product, and supplement your pet takes.

Recorded cautions

Concurrent use of other NSAIDs or corticosteroids; Bleeding disorders or upcoming surgery; Kidney or liver disease; Gastrointestinal ulcers; Asthma; Dehydrated cats.

Recorded interactions

Other NSAIDs (severely increased toxicity and GI bleeding); Corticosteroids (increased GI ulceration); Heparin and warfarin (increased bleeding risk); Furosemide (reduced diuretic effect); Methotrexate (increased methotrexate toxicity).

These lists reproduce the structured record used by this page and may not be exhaustive. Show your veterinarian the product label and your cat's complete medication list before acting on a number.

Related · 08

Related medications for cats

Sources · 09

Sources & references

The structured medication record behind this page names the references below. The links open the publisher or official resource; they do not turn this page into a prescription for an individual animal.

Source names are shown at the record level; passage-level page and label citations are still being added. Read our methodology and limitations.

Transparency · 11

How this page was made

This page's structured medication record includes Plumb's Veterinary Drug Handbook among its source names. PetDosageChart applies the record's mg/kg values to the entered weight and presents the arithmetic result. A source record is not the same as an individualized prescription or an independent clinical review.

Sources cited
  • Plumb's Veterinary Drug Handbook
  • Merck Veterinary Manual
Calculator formula
Doses scale linearly from a standard basis of 8 mg per kg (3.63 mg per lb) of body weight, given Every 48-72 hours ONLY (NOT daily). The calculator multiplies that basis by your cat's weight and shows an arithmetic comparison with recorded tablet sizes. That comparison does not determine whether a tablet is scored, splittable, or appropriate for your pet.
Editorial owner
Prepared and maintained by the PetDosageChart editorial team, a software-led publisher and not a veterinary practice.
DVM review status
Not independently DVM-reviewed. A named reviewer and review date appear here only after a confirmed review.

More on our methodology and editorial process — how we source, calculate, and review cats dosage data.

Safety · 10

More resources