Jo Marshall, CVT, NREMT
Senior Veterinary Information Specialist
Hi, my name is Jo and I pick mushrooms. I pick them every day! I gather them up when I do my daily dog poop patrol in the yard. It is no small feat to do the mushroom gathering that I do, as there have been times that I have gathered a couple of gallons of mushroom a day – extreme, I know! I am admitting my extreme OCD behavior, but I want to explain to you why I am so obsessed with picking mushrooms!
This little nose on the ground, never stop moving and hunting, Viszla named Remi is the reason! Remi never stops and is always bringing me some treasure she finds in the yard. But there are 3 other reasons, Edie, the Cocker Spaniel, Tramp, the Labrador and Clifford, the who knows what he is mixed breed dog that also live here.
Mushrooms are a big deal, especially when you do not know what they are, and you have dogs eating them! Easy, you say, just find out if they are poisonous, you say. Not so easy, I say. Mushrooms are very difficult to identify. Identifying a poisonous mushroom from a non-poisonous mushroom is difficult and beyond the scope of the great majority of pet owners and most veterinarians. There is no skull and crossbones marking on the bad ones! And there are many, many varieties of mushrooms. Here is an example of what I picked one evening in my yard. This is just what I think are the different varieties I found in one picking. It is not the total that I gathered up but rather a sampling of the mushrooms gathered. In reality the total harvest was closer to a nearly full 2gallon bucket!
I put a quarter there amid the mushrooms, so you could get an idea of the size of these little fungi. As you can see they are all different sizes with variations in colors and shapes. In fact, there are many thousands of species of mushrooms and up to 100 toxic species in North America. 
Now let’s talk about what happens when your dog eats one of these unidentified mushrooms? The most important thing is to act fast with these ingestions because we have no idea what we are dealing with because most mushroom identification need to be done by a professional and that may not be easily done quickly. Consequently, we need to treat as if it is a potential toxicity now and not wait for identification.
The first step is aggressive decontamination of the pet and only if it is safe for this pet. There are instances that are not safe to induce emesis. For example; dogs that are showing signs of toxicity, dogs that are under 10 pounds or are brachycephalic. If decontamination is not done immediately following ingestion, then get to your closest clinic. because of the risk of clinical signs within 15 minutes to 2 hours following ingestion. We do not want to see a dog develop signs of toxicity as they are starting to vomit. If you induce emesis at home, then get to your veterinarian quickly for continued care. Make sure you collect the vomit that was produced and bring it with you to the clinic, so it can be checked for any mushroom pieces. At this point your veterinarian and one of our toxicologists will start treating your pet to prevent absorption of the toxicant and supportive care if signs start to occur.
Ok, so now let’s talk about what needs to happen to identify a mushroom. As I have said, any stomach contents or vomitus need to be gathered up, refrigerated, and labeled “DO NOT EAT”.
Then we need you to gather any mushrooms or mushroom pieces located in the area where your pet ate the mushrooms. These should be gathered in a paper towel and placed in a paper bag (not plastic) and again, refrigerate and labeled “DO NOT EAT”. It is important to have all parts of the mushrooms as many times, to differentiate between some species, the top, the bottom and the underside of the cap are needed to identify definitively what species we have and the toxic component of that mushroom.
Here are 2 images of different types of mushrooms so that you can see some of the subtle differences in the various species.
The next step is to photograph the area where the mushrooms were gathered. Different areas can grow different mushrooms. Area where there is downed wood or manure piles, or various tree cover produce different types of mushrooms. Here are a few photos from my yard.
This is an area with a heavy cover of pine needles beneath a grove of ponderosa pine. The mushrooms in the following manure pile are certainly different than the former. The third photo is an area of irrigated lawn and some of the mushrooms in that area. Make sure that when you photograph the areas that you get both closeups and more wide range to show any trees or foliage in the area.
Then the photos, the mushrooms and mushroom pieces along with the stomach contents should go to a mycologist for identification.
Now let’s talk a little about the types of mushrooms and the types of toxicities that we see and some of the clinical signs.
We can see some mushrooms cause gastrointestinal upset, these are not generally fatal, but they can sure cause vomiting and diarrhea. These are not a huge concern beyond potential dehydration secondary to the vomiting and diarrhea.
The next group of mushrooms are hallucinogenic mushrooms or “recreational mushrooms”. With this mushroom ingestion, the dog can become very weak, vocalizing and crying out, walk like they are drunk and can become aggressive. These guys need hospitalization and in most cases, they do well with appropriate care.
A group of highly toxic mushrooms, are those that contains cyclopeptides. With these mushrooms we generally do not see signs of poisoning immediately. We can see vomiting, diarrhea, and bloody diarrhea initially but then signs proceed to liver and renal failure. These are the type of mushrooms that very few animals (or people) survive.
Another very toxic group of mushrooms contain hydrazine toxins. Within a couple of hours of ingestion, we can see vomiting and diarrhea that quickly change to lethargy and seizures followed by liver necrosis in the late stages of toxicity. The survival of ingestion of this mushroom is dependent on the timeliness of appropriate treatment.
The next group of mushrooms contain isoxazoles. This is one of the mushrooms that cause havoc very quickly and we can’t induce emesis at home. These need to go directly to your clinic for stomach pumping to prevent aspiration and further complications. These mushrooms can quickly result in seizures, paresis, paddling, chewing, and aggression. These guys need intensive care very quickly to survive this toxicity.
The last one is the muscarinic toxins. Generally, we will see signs of salivation, tearing eyes, uncontrolled urination, diarrhea, gastrointestinal distress and vomiting. Survival of this ingestion is dependent on the severity of the signs and how quickly the patient is treated.
I know you are all wondering why we have so many mushrooms in our yard and the perfect storm that we have had to result in the rapid growth of mushrooms. I live in western Montana and we have been, at times, surrounded by fires so we constantly irrigate our pastures and yard during the fire season to prevent fires from spreading. We have had times when there are hot embers and ash scattered by the wind, land in our yard. Keeping things green and lush, certainly help prevent the spread of wildfire, but it also causes a bumper crop of potentially harmful mushrooms.
Mushroom ingestion can be very serious or may be nothing but there is also a very good chance that it can be fatal! Please ask for assistance with these exposures so it is managed appropriately to account for the worst possible scenario and save your pet. Contact us at 800-213-6680 for assistance while on your way to your veterinarian so that we may have a toxicologist available immediately to assist in care of your pet. We are here 24/7 to assist you in keeping your pet happy and healthy.
