Why is activated charcoal given to dogs and cats after they’ve eaten something they shouldn’t?

Instructional Guide

Students will learn how to identify signs of chocolate toxicity in dogs. They will explore why veterinarians induce vomiting and feed activated charcoal to sick patients that have ingested chocolate. The lesson will include a short story along with activities that are meant to engage the reader and be helpful learning tools.

Intended Grade Level

This lesson is intended for older elementary students (grades 3-5). Students should have a basic understanding of what vomiting is, how food is digested, and how medications can be given.  Students should also have a basic knowledge of the causes and symptoms of abdominal pain. Finally, students should also be aware of what dogs and cats are normally fed (ex. kibble, dog chow, canned cat food, etc.).

Learning objectives

1. Students will be able to explain why dogs and cats should not eat chocolate
2. Students will be able to identify signs of chocolate toxicity in dogs and cats
3. Students will be able to explain why activated charcoal is used to treat chocolate toxicity
4. Students will be able to describe how activated charcoal is fed to sick patients

Lesson Format

1. Students will read the story on the lesson page as a group, and work through the learning activities as they come up either independently or within a small group (25 minutes).
2. Once through the lesson, the assessment will focus on working through a storybook of Melon’s story, answering questions when prompted within the self-contained module (10 minutes).

Lesson Background

Dogs and cats should not eat chocolate because chocolate contains a chemical called theobromine. Interestingly, the more bitter and darker the chocolate is, the more theobromine it contains. Theobromine falls under the class of chemicals known as methylxanthines, which also includes caffeine; this class of chemicals can have effects on the heart and muscles. Since this chemical cannot be processed in a dog or cat in the same way it can be by our bodies, the effects of theobromine can become toxic in pets when chocolate is ingested.

Clinical signs of chocolate toxicity in dogs and cats usually occur within 6-12 hours after ingestion. Signs of toxicity can include nausea, vomiting, diarrhea, lethargy, increased urination, panting, and/or increased breathing rate. More severe signs of chocolate toxicity can include racing heart rate, abnormal heart rhythm, muscle tremors, increased body temperature, seizure, collapse, coma, and death.

When a patient is brought to the vet with signs of chocolate toxicity and a history of chocolate exposure, the vet will begin treatment right away. The vet will first use drugs to induce vomiting and expel as much of the undigested chocolate from the patient’s GI system as possible. The vet may also encourage the patient to eat a slurry of activated charcoal with water and canned food.

Activated charcoal is given to the pet to decrease the absorption of any remaining toxin in the digestive tract. By feeding a slurry of activated charcoal to patients with acute chocolate toxicosis, the activated charcoal will absorb the theobromine and decrease the effects of poisoning. Treatment with activated charcoal can be effective up to four hours after chocolate consumption.

With quick and efficient care, the overall prognosis for a dog or cat is good. At home, pet owners should be sure to store their chocolate in a safe place that is not easily accessible to their pets so that chocolate toxicosis is avoided.

Activities

Students should complete the learning activities while they read the story. Students can work by themselves or in small group (2-3 students).

Common misconceptions and challenge points

Students may be confused as to why chocolate is bad for dogs and cats. Theobromine is a chemical that is toxic to dogs and cats, and since they can’t digest it properly, the build up of theobromine in their systems can lead to clinical signs. Explaining this in terms of food items, such as grass, that other animals can digest but not humans and would result in an upset stomach if consumed in excess might help in explaining this concept.

Getting a dog or cat to eat activated charcoal might be difficult to imagine, but vets take advantage of certain foods that dogs and cats particularly love in order to administer foul-tasting medicines along with them. For instance, dogs tend to really like liquid baby food, peanut butter, and spray cheese, while cats tend to really like Churu and Delectables Squeeze Up treats. Activated charcoal mixed with these treats increases its palatability and eases administration.

Students may also have difficulty understanding the concept of chemical binding. It may be helpful to explain this concept by sticking two things together, such as balls of tape or velcro, that can represent particles of activated charcoal and toxins binding to each other.

Assessment

Students will work through a storybook of Melon’s story, going over what has happened and answering questions when prompted about what has caused Melon’s symptoms.

Further Exploration

For more information on topics covered in this lesson, check out these links:

• Activated Charcoal for Dogs and Cats on PetMD
• 10 Facts About a Dog’s Digestive System: Vet Approved Guide on Dogster.com
• People Foods Dogs Can and Can’t Eat on the AKC website