Blue-Green Algae: Know The Risks To Your Dog

Yellow Labrador Retriever on a blue-green algae background

Summer is a great time to get out and enjoy our lakes, ponds, and ecosystems while hiking with your dog … but you need to be aware of blue-green algae poisoning in dogs…

Also known as cyanobacteria, these algae can kill your dog … so you need to be able to recognize it to stay clear!

So I want to share with you how to spot this water “monster” and what do if your dog comes into contact with it.

What Is Blue-Green Algae?

Chances are you have an idea of what algae look like.

Blue-green algae look a “pea soup” scum that floats on the water … but it’s actually bacteria. In fact, it’s bacteria that can photosynthesize.

The bacteria grow and develop into large colonies that form blooms.

These blooms are often found near the shores because the wind moves them along the surface.

It’s icky to think about swimming in it … unless you are a dog and “pond scum” is the new perfume of the day.

So you need to be on the watch for it … because your dog won’t care that it’s slimy and smelly.

Not all blue-green algae blooms produce toxins … but there’s no way to know for certain with the naked eye which ones are harmful.

If you see a sign posted near the water with a blue-green algae warning … RUN!

… well, you should at least leave the area to be safe.

The sign means that a lab test was run to confirm toxic blooms are present and public health posts these signs to keep us safe.

We become very ill when our skin comes into contact with toxic blooms.

The same is also true for your dog … but it can be deadly if they lick or drink any of it.

Remember wild animals will be affected too … so if you‘re out near water and you see dead animals (even fish or birds) … don’t let your dog in the water! 

What Makes Some Blue-Green Algae Toxic?

The toxins produced that cause illness are Microcystins and Anatoxins.

Microcystins can cause:

  • liver damage and possible liver failure
  • vomiting
  • diarrhea and or bloody diarrhea
  • pale or jaundice gums ( mucous membranes)

Anatoxins can cause these neurological issues:

  • muscle tremors
  • seizures
  • paralysis

Symptoms Of Blue-Green Algae Poisoning in Dogs



Both toxins can cause symptoms in your dog and in as little as 30 to 60 minutes after your dog is exposed to the toxins.

Symptoms associated with microcystins may take up to 12 to 24 hours to appear … but it’s still critical to take your dog to a vet as soon as possible.

In a perfect world, you will be able to avoid these algae but if your dog is out of sight with access to water … you need to look out for these symptoms:

  • Diarrhea
  • Vomiting
  • Blood in stool or black, tarry stool
  • Pale mucous membranes
  • Jaundice
  • Seizures, muscle tremors, muscle rigidity, or paralysis
  • Disorientation
  • Coma
  • Excessive salivation or tearing
  • Blue discoloration of the coat, skin and mucous membranes
  • Difficulty breathing

Find Out If Blue-Green Algae Is In Your Area

The Environmental Working Group website has a ton of information about blue-green algae … including a map that shows where blue-green algae has been found. Click on the link and you’ll see how it has increased from year to year!

The map below shows the 2019 US incidence.

Map of the United States with blooms of the Blue-Green algae in 2019
EWG Algae Blooms 2019

How To Test Your Home Pond Or Lake

In case you’re wondering if your pond or lake at home may be contaminated … not to worry!

There’s an easy home test that you can start with here. You can also reach out to your local health officials to find out about lab tests in your area.

What to Do If You Suspect Blue-Green Algae Poisoning

  1. Rinse your dog off with fresh water as soon as possible to remove as much bacteria as you can.
  2. If you’re not sure if your dog licked or drank any water … follow the instructions below. You might also want to talk to your holistic vet. Meanwhile watch your dog carefully for any signs of illness.
  3. If your dog did lick or drink any water ... you need to get him to the vet as soon as you can. But follow the instructions below for some things you can do right away that can help!

Caution: If your clinic is closed, go to a 24-hour emergency clinic. Don’t wait till morning. That may be too late. Call ahead to let the clinic know you’re on your way and why. 

But right away … there are things you can do to start helping your dog. 

Note: These remedies don’t replace veterinary care. They can help reduce symptoms, but your dog will still need emergency veterinary care. 

Picture of Dee Blanco

We reached out to homeopathic veterinarian Dee Blanco DVM for her advice. 

Read this section before you have an emergency, so you can buy what you need to be prepared! 

Supplies To Carry With You (Shopping List) 

  1. Hydrogen peroxide. Buy 3% hydrogen peroxide at any pharmacy.

2. Activated charcoal. Try to find one of these products:

  • UAA Universal Antidote Gel, available at Amazon and veterinary suppliers. This comes in an easy-to-dose  syringe that you can use right in your dog’s mouth. 
  • Toxiban (available at Amazon, Walmart or other sellers). If you can get Toxiban with sorbitol, that’s better. It’s available at some veterinary suppliers, like this one.
  • Or, buy a powdered charcoal at any health food store ,,, and take a small amount of soft food to mix it with (see Dosing Charcoal below)

3. A syringe or small baster to give either hydrogen peroxide or charcoal, as needed. 

4. Homeopathic remedies you might need (available at apothecaries, health food stores (like Whole Foods, Vitamin Shoppe) and many online suppliers, including Amazon)

  • Nux vomica 30C or 200C
  • Arsenicum album 30C or 200C
  • Aconite (Aconitum napellus) 30C or 200C
  • Carbo vegetabilis 30C or 200C

Remedies To Help With Blue-Green Algae Poisoning

Note: Follow these recommendations if you see any rapid onset symptoms when your dog’s been in the water – even if you didn’t see blue-green algae! It can hide for a long time in corners and other less visible places.

If your dog has no symptoms but you think he might’ve drunk some water … 

Immediately give a dose of activated charcoal. This is best used within an hour or two of exposure.

Charcoal binds to toxins and can help remove them from his body. If he has swallowed some toxic water, it could help him eliminate the toxins.

If he hasn’t drunk any water, the charcoal won’t hurt him. 

Dosing Charcoal

Depending on which charcoal option you bought, here’s how to give it:

Amount: 1 ml per lb of body weight.  It’s a good idea to calculate how much you’ll need ahead of time. 

  • UAA: use the easy-dose tube to dose it right in his mouth
  • Toxiban: you can use the container to put it straight in his mouth, or use a syringe. Be aware that it’s liquid and can be messy. 
  • Powder: mix into a slurry with a little soft food your dog loves (a little canned food, pumpkin, yogurt – just a little, though). This is only for animals who can still lick and eat. 

If you know your dog has swallowed some water that you suspect is toxic …

Caution: If your dog has a seizure or is unconscious, don’t give either hydrogen peroxide or charcoal. He needs to be able to swallow the liquids.  

#1 Immediately give hydrogen peroxide to induce vomiting. 

Only do this if it’s been less than 2 hours since he drank the algae water. If it’s been more than 2 hours go straight to #2, activated charcoal.

  • Amount: using a syringe, give 1ml (or cc) per pound of body weight of hydrogen peroxide.
  • The easiest way to do it is to hold his head level or slightly tilted … then use the syringe to squirt the peroxide into the side pouch near the corner of his mouth. Don’t tilt his head back too far … you don’t want him to aspirate the peroxide.  
  • He should vomit quickly. If not, repeat that dose once within 15-20 minutes.
  • If nothing happens the second time … switch to dosing the activated charcoal. Don’t wait too long. 

#2 After the peroxide, give a dose of activated charcoal (see Dosing Charcoal above).“

Don’t be alarmed if your dog vomits or has diarrhea. He needs to get the toxins out of his body. When you get to the vet, they’ll make sure he’s hydrated … and will give fluids if needed. 

But you can give a homeopathic remedy to support him. 

#3 At the first sign of vomiting or diarrhea give one of these homeopathic remedies:

(See Giving Homeopathic Remedies below for how to dose them.)

For vomiting only: give Nux vomica 30C or 200C

For diarrhea, or diarrhea plus vomiting: give Arsenicum album 30C or 200C

Give the remedy every 15 minutes until you get to the vet. 

#4 If Your Dog Has Other Symptoms …

If your dog has a seizure …

Give the homeopathic remedy Aconite 30C or 200C. 

If Aconite doesn’t help within a few minutes: 

Give Nux vomica 30C or 200C.

If your dog becomes unconscious or stops breathing … 

This is obviously an extreme emergency so if you’re not already on the way to the vet, go immediately. But you should also try giving this remedy on the way: 

Carbo vegetabilis 30C or 200C

Giving Homeopathic Remedies

Most homeopathic remedies come in little pellets. Some dogs will take a dry dose in pellet form and for others a wet dose is easiest. 

Dry dose

If you know your dog will take the pellets, just carry the containers with you. 

Twist the tube until about 3 pellets fall into the cap, then remove the cap and tip the pellets into your dog’s mouth (without touching them with your hands). A good way to do this is to pull out the lower lip near the corner of the mouth. You’ll find a convenient little “pouch” where you can tip the pellets.

Wet dose

If your dog’s likely to spit the pellets out, it’s best to be prepared by making a wet dose. Take a clean amber glass dropper bottle. Add a few pellets to the bottle, fill it about ¾ full with spring or filtered water … then top up the rest with brandy or vodka to preserve it. Shake the bottle vigorously about 10-20 times … and shake it again before each dose.  

Once You’re At The Vet

Let your vet take over and do what’s necessary to save your dog. This is an emergency … and not the time to be quibbling about sticking with natural care. 

However, the toxins in the algae put stress on your dog’s liver and can cause organ damage. So, when you get a chance … ask your vet to make sure your dog gets liver support. 

Many vets will give Sam-E, N-Acetyl-Cysteine (NAC) or vitamin C. If they don’t, ask if you can bring one or more of these supplements for them to give at the clinic. 

Not all dogs die from algae poisoning. Some dogs with healthy immune systems may not even get sick. But the dogs who are affected can die very quickly. So you need to be prepared. 

And again, don’t waste time waiting to get to your regular vet.  Find the closest clinic that’s open and go straight there. 

Here’s a veterinary article about a dog who survived … but as you can see, the treatment was very intensive, including being on a ventilator for 18 hours! 

Now you know why I wanted to share this serious summer concern and what to do … But don’t stop enjoying the great outdoors with your dog … just keep watch!

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