Is Fly Bait (Methomyl) Toxic to Cats and Dogs?
Methomyl fly bait is severely toxic to both cats and dogs — a carbamate poison causing drooling, tremors, and breathing failure within an hour. Any ingestion is a race to the vet.
Potentially life-threatening — treat any exposure as an emergency.
Potentially life-threatening — treat any exposure as an emergency.
In an emergency, do not wait.
Medical disclaimer: This tool is for general information only and isnot a substitute for veterinary diagnosis or treatment. Toxicity depends on the amount, your pet’s size, and health history. If your pet may have ingested something harmful, contact your veterinarian or a poison control hotline ((888) 426-4435 / (855) 764-7661) immediately — do not wait for symptoms to appear.
What is Fly Bait (Methomyl)?
Methomyl fly bait is severely toxic to both cats and dogs — a carbamate poison causing drooling, tremors, and breathing failure within an hour. Any ingestion is a race to the vet.
Also known as: methomyl, fly bait granules, golden malrin, blue fly bait, fly strips, flying insect bait, lannate, carbamate fly bait.
Symptoms to Watch For
🐕 In Dogs
- Excessive drooling, vomiting, and diarrhea within minutes to an hour
- Pinpoint pupils, slow heart rate, and trembling
- Wobbliness progressing to weakness and collapse
- Difficulty breathing and seizures without rapid treatment (carbamate poisoning)
🐈 In Cats
- Sudden heavy drooling, vomiting, and diarrhea
- Pinpoint pupils, tremors, and slow heart rate
- Weakness, wobbliness, and collapse
- Difficulty breathing and seizures without rapid treatment
What to Do If Ingested
- Call a veterinarian or poison hotline IMMEDIATELY — this is a cholinesterase-inhibiting poison.
- Bring the product name (methomyl percentage) and estimate the amount eaten.
- Do not induce vomiting unless a veterinarian instructs you to.
- Keep the pet calm and get to the clinic — time to treatment is everything.
Steps apply to both cats and dogs. When in doubt, call a vet or poison hotline before acting. Have a cat? Run the Pet Poison Triage Wizard for cat-specific steps.
When to Call the Vet Immediately
Call your veterinarian or a poison control hotline right away if you notice any of these:
- Any fly bait granules were eaten — even a few
- Drooling, trembling, or pinpoint pupils
- Collapse, seizures, or breathing difficulty — emergency clinic now
Frequently Asked Questions
Frequently Asked Questions
Why is fly bait so much more dangerous than ant bait?
Methomyl — the active ingredient in popular blue or golden fly-bait granules — is a carbamate, the same chemical family as the dangerous organophosphate insecticides: it shuts down the enzyme that regulates nerve signals. Commercial fly baits run 1% methomyl and are mixed with sugar to attract flies — which also makes them attractive to dogs. Ant and roach baits typically use far less toxic actives at tiny doses (see our ant & roach bait page).
I have heard of people using fly bait to poison coyotes. Is that why it is so dangerous?
Unfortunately yes — methomyl fly bait mixed with meat or eggs has been widely misused to kill predators, and it is banned for that use. The same lethality applies to any dog or cat that finds it. If you suspect your pet was deliberately poisoned with fly bait, tell your veterinarian — law enforcement treats malicious poisoning as a crime, and knowing helps the vet choose the right emergency treatment.
What does treatment look like?
Carbamate poisoning is treated with atropine (an antidote that blocks the poison at nerve receptors) plus decontamination, IV fluids, and seizure control. Recovery with fast treatment is genuinely possible — but the window is short, since breathing muscle failure can develop within an hour. This is a go-now emergency, not a watch-and-wait one.
Sources
This entry is reviewed against the following authoritative veterinary sources.
Last reviewed: 2026-10-16