Summer Pet Poisons

Summer is finally here, and with that comes a myriad of fun outdoor activities along with home and garden projects. While summer is meant for relaxing at the lake with friends picnicking, watching fireworks, and cleaning up and readying yards and gardens for the upcoming growing season, it’s potentially fraught with toxic exposure to your pets! Summertime brings new opportunities for potential pet exposures to harmful and dangerous substances. Outside pets should be confined to a safe area or supervised at all times. Bottle, bags, and other containers should be tightly closed and locked away in the garage or basement.

During the summer months, Pet Poison Helpline® is inundated with calls involving yard and garden products (including bone meal, fertilizers, and insecticides), mulch and compost pile ingestions, and exposures to outdoor plants and mushrooms. As with all poisonings, early recognition and decontamination are key to a successful outcome. Here is some basic information for you to know about when dealing with these exposures.

Salt Water Toxicity

While it’s probably not at the top of your toxin lists, salt water is a dangerous poison, particularly if you take your dog to the beach! If your dog loves to play on the ocean beach, heed caution. Dogs don’t realize that salt water is dangerous, and excessive intake can result in severe hypernatremia, or salt poisoning. While initial signs of hypernatremia include vomiting and diarrhea, salt poisoning can progress quickly to neurologic signs like walking drunk, seizures, progressive depression, and ultimately, severe brain swelling. Help avoid the problem by carrying a fresh bottle of tap water and offering it to your dog frequently while he’s frolicking on the beach.

Slug and Snail Baits

Slug and snail baits are commonly used on the West coast and in warm-weather conditions, and are available in a variety of forms (pellets, granular, powder, and liquid). The active ingredient is typically metaldehyde, which is toxic to all species (particularly dogs). When ingested, metaldehyde results in clinical signs that resulted in the nickname “shake and bake.” Within 1 to 2 hours of ingestion, clinical signs of salivation, restlessness, vomiting, and incoordination are seen, which then progress to tremors, seizures, and secondary severe hyperthermia. Generally, the prognosis is favorable if treatment is quickly and aggressively implemented.

Mole and Gopher Bait

Surprisingly, most veterinary professionals aren’t very familiar with mole and gopher baits, which typically contain zinc phosphide. Other types may contain bromethalin. Neither of these active ingredients have an antidote and both can result in rapidly developing, life-threatening symptoms. Zinc phosphide is often manufactured in a poisoned “peanut” form but can also be found in a pelleted or powdered form. When zinc phosphide combines with gastric acid, it results in rapid phosphine gas formation within the stomach. This toxin is made worse by the presence of food in the stomach, so make sure acutely poisoned pets aren’t fed anything when this toxicity occurs! This gas causes severe gastrointestinal inflammation, abdominal distension, and cardiovascular insufficiency (similar to symptoms of a GDV or bloat). Pulmonary congestion and edema may also occur. Clinical signs develop rapidly within 15 minutes to several hours and include vomiting, salivation, abdominal discomfort, bloating, depression, labored breathing, tremors, and weakness. Once clinical signs have developed, the prognosis is guarded.

A word of caution to veterinary staff: second hand phosphine gas exposure can result in significant health risks to healthcare providers working in unventilated areas. By the time the phosphine gas odor has been recognized (which smells like rotten fish and garlic), there has already been significant exposure to staff. So, whenever inducing emesis in a patient with this toxicity, do so in a well ventilated, outdoor area, and contact Pet Poison Helpline® for more information on treatment.

Flea and tick products

Take the time to read the product label before applying topical flea and tick products to pets, especially cats. There are a number of “spot on” products on the market labeled “for use in dogs only”. While safe when used according to package directions, inappropriate use of these products on cats can result in illness and death. Consult with your veterinarian before using flea and tick product on very young or old pets, pregnant or nursing pets, or those with a chronic illness.



There are various types of mushrooms located throughout the United States that may be non-toxic; however, other types of mushrooms may be gastric irritants, hallucinogenic, or hepatotoxic (from cyclopeptides, hydrazine toxins, isoxazoles, or psilocybin compounds). Clinical symptoms are dependent on the species of mushroom ingested, the specific toxin within that mushroom, and the individual’s own susceptibility.  Early clinical signs include vomiting, diarrhea, abdominal pain, ataxia, CNS depression, tremors, and seizures, with liver and renal damage occurring later. One can collect all the pieces of the mushroom in a paper towel, place them in a labeled (DO NOT EAT! POISONOUS!) paper bag, and refrigerate the sample for future possible identification.



Many pets are frightened by the noise from fireworks and should be kept in a safe, quiet environment when fireworks are used. Some pets, however, seem to enjoy the commotion and physically chase or chew on fireworks. Depending on the product, this can result in thermal or chemical burns to the paws, mouth, face, and gastrointestinal tract or other problems such as bone marrow depression and kidney failure.


Tomato plants are in the Nightshade family and contain tomatine. Tomatine is found in concentrations of up to 5% in the leafy greens, the fruit blossoms, and in small green tomatoes; this concentration rapidly decreases as the tomato ripens. When stems, vines and green fruit are ingested, clinical signs can include gastrointestinal irritation, ataxia, and weakness. Treatment is purely supportive with an overall good prognosis. Rhubarb leaves contain oxalic acid, calcium oxalate and potassium oxalate and can result in oral and gastrointestinal irritation causing vomiting and diarrhea.  Holiday ornamental plants such as poinsettias and Easter lily are often put outside for the summer. Ingestion of poinsettia stems and leaves may cause some mild gastrointestinal irritation and vomiting. Ingestion of all parts of the Easter lily causes depression, vomiting and diarrhea in cats. Left untreated most cats die of kidney failure. Tulips (bulbs), Lily of the valley, Oleander, Kalanchoe, and Azaleas are spring and summer plants that can be deadly to pets if ingested in large enough quantities. Dogs should be watched carefully when these plants are being cared for.

Grapes (or raisins)


Grapes or raisins grown in home gardens can present significant concerns when dogs ingest them. Although the mechanism of action is not clearly understood at this time, grapes can result in anorexia, vomiting, diarrhea, and potentially severe acute renal failure. The toxicity is not necessarily dose-dependent, and symptoms can occur with even small ingestions.


Summer is the time when pets dig up or discover long forgotten rodenticides brought to the surface by melting snow or spring rains. Whatever the case, once found they are harmful to pets. Several different types of rodenticides are found on the market, but those containing strychnine and zinc phosphide are the most deadly. Generally these products have been placed below ground to kill gophers or moles and are found by dogs that dig or forage under buildings. Ingestion of these products is a life threatening emergency. There are a number of products designed to kill rats and mice in and around your house and garage. As a rule, this type of product contains an anticoagulant and can be deadly if not treated appropriately. Fortunately, an antidote is available for ingestion of anticoagulant products.


Herbicides rarely result in concerns when used and applied according to the label directions, provided pets have been kept off the treated surfaces until the applied product has dried completely. However, when applied inappropriately, or when pets chew containers of concentrated product, there is a significant increase in the likelihood of potential toxicity. Clinical signs are dose and product dependent.

Blue–green algae or Cyanobacteria

Growth of toxic algae can be found in both fresh and salt water throughout the warm regions of the world. Blue-green algae becomes concerning when algae accumulates on the surface of the water during hot, dry weather with wind that can shift concentrated algae mats along the shorelines. Affected water may have the appearance of pea soup with thick layers of algae on the surface. Blooms of blue-green algae can contain hepatoxins and/or neurotoxins, depending on the species. Exposures occur when dogs ingest or swim water that contains the cyanobateria. Clinical signs with the hepatoxin variety are vomiting, diarrhea, lethargy, weakness, shock, icterus, and potentially death within 24 hours to several days. Clinical signs seen with ingestion of neurotoxin species occur acutely with onset of tremors, lethargy, seizures and respiratory distress and death within a hour.


Spring and summer preventative wellness visits to the clinic are the perfect time for client education – these visits also serve as an opportunity to reminder pet owners about potential hazards that may have been out of sight during the colder months of the year. Education of staff and pet owners has proven to be the best method of preventing exposures to potentially harmful substances in animals. This coupled with information on when to seek prompt veterinary intervention and care will help keep your patients happy and healthy through the busy summer months ahead!