Vomiting After Flea Treatment: What To Do For Dogs and Cats

Why this happens
Some pets get mild tummy upset after a new flea, tick or worm treatment. Chews can cause brief nausea in a small number of pets. Spot-ons rarely cause vomiting, but cats may drool if they taste the product during grooming. Most mild signs pass within a day.

Before you give a chew

• Give with or soon after a meal.

• Use the correct weight band.

• Keep the dose calm and low stress.

• Avoid new foods on the same day.

If your pet vomits after a chew

• If it is one episode and your pet is seemingly okay, offer water and watch closely.

• Do not give a second full dose unless the label or your vet advises it.

• If vomiting repeats, your pet seems unwell, or you are unsure about redosing timing, call your vet.

• Next time, give the chew with a proper meal. You can also ask about switching to a different application.

If you use a spot-on and your cat drools

• Brief drooling can happen if a cat licks product from the coat.

• Separate pets after dosing and apply at the back of the head where they cannot reach.

• Offer water and monitor. If signs persist or your cat seems unwell, call your vet.

When to see a vet urgently

• Repeated vomiting or vomiting with diarrhoea.

• Blood in vomit, weakness, wobbliness or fast breathing.

• A puppy or kitten, seniors, pregnant pets, or pets with other illnesses.

Trusted options from our range

• Dogs, monthly chew with broad cover: Simparica Trio chewable tablet for dogs

• Dogs, spot-on alternative: Bravecto topical solution for dogs

• Cats, broad monthly spot-on: Revolution Plus spot-on for cats

• Cats, long-acting spot-on: Bravecto spot-on for cats

Safe use checklist

• Weigh your pet and choose the correct pack each time.

• Use dog products on dogs only. Never use dog products on cats.

• Do not combine treatments unless your vet advises it.

• Read the label before every dose. Set reminders so you do not miss dates.

• Keep spot-ons away from children and other pets until dry.

FAQ

My dog vomited soon after a chew. Should I redose
Do not redose without advice. Timing rules vary by product. Ask your vet to confirm what to do next.

Can I switch from a chew to a spot-on
Yes. Plan the change so there is no gap or double dose. Your vet can confirm the timing.

What if my cat licked the spot-on area
Wipe away residue you can reach, offer water and monitor. Apply at the back of the head next time and separate pets until dry.

Will food help prevent nausea with chews
Often yes. Give with or right after a meal and avoid new treats that day.

Need help choosing
Tell us your pet’s age, weight and routine and we will suggest a simple plan. Contact us.