Dr. Justine A. Lee, DVM, DACVECCDog Checkups & Preventive Care

As autumn approaches, so do new potential dangers that pose a threat to your dog and cat. Here are the top 5 fall toxins to be on the lookout for as summer ends. Keep your pet safe by keeping these out of reach!

1. Rodenticides
As the weather gets colder, mice and rats start seeking shelter in warm locations, in other words, your house! Unfortunately, the start of autumn means the start of mouse and rat poisoning. There are several types of active ingredients in these mouse and rat poisons, and they all work (and kill) in different ways. Depending on what type of mouse and rat poison was ingested, clinical signs include:

• Weakness
• Lethargy
• Difficulty breathing
• Coughing blood
• Dehydration
• Inappetance
• Profuse vomiting
• A distended stomach
• Tremors
• Seizures
• Kidney failure
• Even death

I’m never an advocate of using these types of poisons, as they pose a threat to wildlife, pets, and birds of prey (e.g., raptors like red-tail hawks, owls, etc.). I’d rather you use the more humane snap trap–much safer to you and your pet! Learn more about rat poison here.

2. Chocolate

Did someone mention Halloween? The last week of October poses a big danger to dogs, as there’s a greater likelihood that your dog will find the candy stash. While one or two small Snickers® bars aren’t usually dangerous, significant ingestions (e.g., your whole candy bowl) can result in chocolate poisoning in dogs. [To be on the safe side I don’t recommend feeding chocolate of any kind to your pet]. 

The toxic ingredient: methylxanthines (called theobromine) and caffeine. With mild poisoning, clinical signs of chocolate poisoning include:

• Agitation
• Panting
• Vomiting
• Diarrhea

With more significant ingestions, clinical signs of cardiac effects (including a racing heart rate, high blood pressure, and abnormal heart rhythm) or pancreatitis (i.e., inflammation of the pancreas) may be seen. With severe poisonings, chocolate can result in tremors, seizures, and, rarely, death. Keep in mind that with chocolate, the darker and more bitter the chocolate, the more dangerous it is! Semi-sweet chocolate or Baker’s Chocolate contains very toxic amounts of theobromine as compared to milk chocolate or white chocolate. Learn more about Halloween candy basket dangers here.

3. Compost/Mulch piles

I’m all for going green, and am a huge advocate of recycling and composting. However, before you start composting, make sure you have a well secured, fenced off compost pile. If wildlife or your dog ingests the compost directly, it can result in severe poisoning secondary to the mold (containing tremorgenic mycotoxins). Clinical signs of compost poisoning include:

• Drooling
• Vomiting
• Inappetance
• Panting
• Agitation
• Incoordination
• Tremors
• Seizures

4. Mushrooms

While the majority of mushrooms are benign and only result in minor symptoms when ingested, there are a few types that can be deadly (even to humans!) when ingested. Because mushroom identification is so difficult, we veterinarians have to err on the side of caution and assume any mushroom ingested by a pet is toxic.

The most dangerous type? The Amanita mushroom.

Depending on the type of mushroom ingested, clinical signs include:

• Gastrointestinal signs (e.g., drooling, vomiting, diarrhea, abdominal pain)
• Neurologic signs (e.g., walking drunk, tremoring, agitation, seizures)
• Organ damage (e.g., liver or kidney failure)
• Even death

 Learn about other poisonous plants here.

5. Mothballs

As mice and rats come into the house to stay warm, so do moths! Mothballs may look benign, but can be quite dangerous as they typically contain chemicals such as paradichlorobenzene or naphthalene. The classic smell of mothballs is typically due to “old-fashioned” mothballs that contain naphthalene, and these are generally much more toxic than the paradichlorobenzene-containing ones. Clinical signs from mothball poisoning in dogs and cats include:

• Gastrointestinal signs (e.g., drooling, vomiting, abdominal pain)
• Neurologic signs (e.g., lethargy, tremors, etc.)
• Blood changes (e.g., abnormalities in the red blood cells)
• And rarely, even organ failure

When in doubt, if you think your pet was poisoned, call your veterinarian, emergency veterinarian, or the ASPCA Animal Poison Control Center for life-saving care.

Next, learn about the popular peanut butter ingredient that could harm your dog.

If you have any questions or concerns, you should always visit or call your veterinarian – they are your best resource to ensure the health and well-being of your pets.