What Is Amoxicillin and What Does It Treat?
Amoxicillin is one of the most widely used antibiotics in dogs. It is a member of the penicillin family, and the veterinary product (often sold as Amoxi-Tabs or Amoxi-Drops) is FDA-approved for dogs.
Amoxicillin works by disrupting the bacterial cell wall. Bacteria need a strong, intact cell wall to survive; amoxicillin interferes with the enzymes that build and maintain it, causing the bacteria to rupture and die. It is a bactericidal (bacteria-killing) antibiotic effective against a range of common bacteria.
Veterinarians commonly prescribe amoxicillin for dogs with:
- Skin and soft-tissue infections, wounds and abscesses
- Urinary tract infections
- Respiratory infections
- Dental and mouth infections
- Other infections caused by susceptible bacteria
Amoxicillin is closely related to Clavamox. The difference is that Clavamox combines amoxicillin with clavulanic acid, which protects the antibiotic from bacteria that would otherwise destroy it. Plain amoxicillin works well against susceptible bacteria; for infections involving resistant bacteria, your vet may choose Clavamox instead.
Amoxicillin is a prescription medicine. Use the calculator above to understand the typical dose, but a veterinarian should confirm the diagnosis and set the prescription. For more, see PuppaDogs’ guide to amoxicillin for dogs and the related Clavamox dosage calculator.
How the Amoxicillin Dosage Calculator Works
The calculator estimates a dose from your dog’s body weight and the type of infection. It then:
- Shows the dose per administration in milligrams.
- Converts it into tablets or millilitres of oral suspension.
- Lets you choose twice- or three-times-daily dosing.
- Flags penicillin allergy and other relevant cautions.
Enter your dog’s weight, choose the infection type, frequency and the form you have, tick any health considerations, then press Calculate Dose.
How Amoxicillin Doses Are Calculated for Dogs
The Standard Dose
The commonly used oral amoxicillin dose for dogs is approximately:
10 mg/kg of body weight every 12 hours for routine infections, with up to around 20 mg/kg every 8–12 hours for more demanding ones.
The exact dose, frequency and course length your veterinarian chooses depend on the type, site and severity of the infection and the bacteria involved.
Forms and Strengths
- Tablets: commonly 50, 100, 150, 200 and 400 mg.
- Oral suspension (drops): typically 50 mg/mL — convenient for small dogs and accurate dosing. The suspension must be refrigerated and discarded after the period stated on the label.
Amoxicillin Dosage Chart for Dogs
This chart shows the routine dose (10 mg/kg every 12 hours). It is a reference only — your veterinarian’s prescription takes priority.
| Dog weight | Dose per administration | Frequency |
|---|---|---|
| 5 kg (11 lb) | ~50 mg | every 12 h |
| 10 kg (22 lb) | ~100 mg | every 12 h |
| 20 kg (44 lb) | ~200 mg | every 12 h |
| 30 kg (66 lb) | ~300 mg | every 12 h |
| 40 kg (88 lb) | ~400 mg | every 12 h |
How to Give Amoxicillin to Your Dog
- As directed — usually every 12 hours, at consistent times.
- With or without food — either works; giving it with food can reduce mild stomach upset.
- Hide tablets in a small treat, or measure the oral suspension with the supplied syringe.
- Refrigerate the suspension and shake well before each dose.
- Finish the entire course, even if your dog looks better after a few days.
- Missed dose: give it as soon as you remember, then continue on schedule; if it is almost time for the next dose, skip the missed one — never double up.
Side Effects and Safety Warnings
Amoxicillin is generally well tolerated. The most common side effects are mild and digestive — reduced appetite, vomiting, or loose stool — and giving the medication with food helps.
Allergy Is the Key Concern
Because amoxicillin is a penicillin-type antibiotic, the most important safety issue is allergy. A dog with a known allergy to penicillins should not receive amoxicillin, and there can be cross-reactivity with cephalosporins. Tell your veterinarian about any previous reaction so a different class of antibiotic can be chosen.
Stop the medication and contact your veterinarian promptly if you see signs of an allergic reaction — facial swelling, hives, intense itching or difficulty breathing — or severe or bloody diarrhoea.
When to Use Caution
- Penicillin allergy — avoid amoxicillin.
- Kidney disease — the drug is cleared mainly by the kidneys; the dose or interval may need adjusting.
- Pregnant or nursing dogs — generally considered usable, but only on veterinary advice.
Why Finishing the Course Matters
It is tempting to stop an antibiotic once a dog looks better, but doing so is one of the most common mistakes in pet care. Stopping early can leave behind the hardiest bacteria, causing a relapse that is harder to treat, and contributes to antibiotic resistance. Give every dose, for the full length your veterinarian prescribed.
Conclusion
Amoxicillin is an effective, well-established, broadly used antibiotic for canine skin, urinary, respiratory and dental infections, dosed at roughly 10 mg/kg every 12 hours for routine infections and somewhat higher for more demanding ones. The calculator above gives you that estimate and converts it into tablets or oral suspension. Because it is a prescription penicillin-class antibiotic, the diagnosis, dose and course length should always be set by your veterinarian — and the full course completed — for the best chance of a clean, lasting recovery.
Frequently Asked Questions
How much amoxicillin do I give my dog?
The commonly used oral amoxicillin dose for dogs is about 10 mg/kg of body weight every 12 hours for routine infections, and up to around 20 mg/kg every 8-12 hours for more demanding ones. As a guide that is roughly 100 mg twice daily for a 10 kg dog. Your veterinarian sets the exact dose and course length.
What is amoxicillin used for in dogs?
Amoxicillin is a penicillin-type antibiotic used in dogs for skin and soft-tissue infections, wounds and abscesses, urinary tract infections, respiratory infections, and dental and mouth infections caused by susceptible bacteria. A veterinarian should confirm the diagnosis before prescribing it.
What is the difference between amoxicillin and Clavamox?
Clavamox is amoxicillin combined with clavulanic acid. The clavulanic acid protects the amoxicillin from an enzyme some bacteria produce to destroy penicillins. Plain amoxicillin works well against susceptible bacteria, while Clavamox extends the coverage to certain resistant bacteria. Your vet chooses based on the infection.
Can amoxicillin be given with food?
Yes. Amoxicillin can be given with or without food, so you can choose whichever makes dosing easier. Giving it with a little food can help if your dog gets mild stomach upset such as reduced appetite or loose stool.
What are the side effects of amoxicillin in dogs?
Amoxicillin is generally well tolerated. The most common side effects are mild digestive ones – reduced appetite, vomiting or loose stool. The main serious concern is an allergic reaction; contact your vet promptly if you see facial swelling, hives, difficulty breathing or severe diarrhoea.
Can a dog with a penicillin allergy take amoxicillin?
No. Amoxicillin is a penicillin-type antibiotic, so a dog with a known penicillin allergy should not receive it, and there can be cross-reactivity with cephalosporins. Always tell your veterinarian about any previous antibiotic reaction so a different class of antibiotic can be chosen.
Related PuppaDogs Calculators
Continue building your dog’s personalised care plan with these related PuppaDogs calculators:
- Dog Pregnancy / Whelping Due-Date Calculator
- Puppy Weight Predictor (Adult Weight Calculator)
- Heatstroke Risk Calculator for Dogs
- Bloat (GDV) Risk Calculator for Dogs
- Dog Life Expectancy Calculator (Breed, Body Condition, Lifestyle)
- Spay/Neuter Timing Calculator for Dogs (Breed-Specific)
References & Further Reading
The dosing ranges and safety information on this page are drawn from the following veterinary references. Always defer to your own veterinarian and the manufacturer’s label for your specific product.
- Amoxi-Tabs / Amoxi-Drops (amoxicillin) – FDA-approved veterinary label, Zoetis.
- Plumb DC. Plumb’s Veterinary Drug Handbook. 10th ed. Hoboken, NJ: Wiley-Blackwell, 2023 – amoxicillin monograph.
- Merck Veterinary Manual. Penicillins and beta-lactam antibiotics in animals. merckvetmanual.com.
- International Society for Companion Animal Infectious Diseases (ISCAID). Antimicrobial use guidelines for dogs and cats.
- PuppaDogs. Amoxicillin for Dogs: Benefits, Dosage, Side Effects, and More. puppadogs.com.
