Is Blue-green Algae (Cyanobacteria) toxic to dogs?

Extreme severity No safe amount — No amount is considered safe.

Yes. Even a small amount can be life-threatening — treat any exposure as an emergency and contact a vet immediately.

Symptoms to watch for

Vomiting
Diarrhea
Blood in stool
Black tarry stool
Weakness
Pale mucous membranes
Jaundice
Liver failure
Muscle tremors
Seizures
Disorientation
Coma
Muscle rigidity
Paralysis
Cyanosis
Difficulty breathing
Death

How vets treat it

Immediate veterinary care is imperative as there is no antidote. Treatment includes aggressive supportive care, anti-seizure medication, and oxygen therapy.

Why it's dangerous

Microcystins cause severe liver damage and failure, while anatoxins act as neurotoxins leading to respiratory paralysis and death within minutes to hours.

Toxic compound: Microcystins and Anatoxins

Good to know

Blooms often appear as 'pea soup' or spilled paint. Even a few mouthfuls of contaminated water can be fatal. Hunting dogs are at higher risk.

Sources

Pet Poison Helpline

This page is informational and is not veterinary advice. If your pet has been exposed to something risky, contact your vet or an animal poison control line right away.

More substances toxic to dogs

African Wonder Tree Extreme severity Andromeda Japonica Extreme severity Angel's Trumpet Extreme severity Autumn Crocus Extreme severity Everything toxic to dogs →

Packaged food? Scan the barcode.

StrawPaw's food scanner reads the barcode on packaged products and flags ingredients that are risky for dogs and cats — before anything reaches the bowl.

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