Toxic Foods for Dogs and Cats

Several foods, although harmless to humans, can pose a serious threat to the health of our pets. In the last decade, worldwide cases of food poisoning due to accidental ingestion of harmful foods for pets have been reported. Chocolate and cocoa-based products were the most implicated, followed by products sweetened with xylitol, onions and garlic, grapes and raisins, macadamia nuts, and ethanol. In general, poisoning episodes were due to the public’s lack of knowledge about the danger that these products can pose to the health of small animals. Dogs and cats can accidentally ingest harmful foods due to their wide presence in households. Dogs are less selective in their eating habits, so they are more affected than cats. While some foods, such as chocolate, have long been known to cause poisoning in pets, others, such as grapes, were considered unlikely to cause problems. In this review, we will address methylxanthines, providing an overview of symptoms and subsequent treatment.

Methylxanthines (caffeine, theobromine, and theophylline)

Methylxanthines are a group of central nervous system stimulant alkaloids. Theophylline is commonly found in tea, theobromine in cocoa seeds, and caffeine in coffee and as an additive in many soft drinks.

The vast majority of poisoning cases in dogs occur as a result of chocolate ingestion. Although poisoning can also occur in cats, dogs are more commonly affected due to their eating habits. Intoxication episodes often occur during celebrations when there is a higher presence of chocolate at home (chocolates, cakes, and other sweets). In addition to theobromine, chocolate contains caffeine, but in much lower concentrations. It is important to note that the concentrations of theobromine and caffeine vary depending on the type of chocolate:

• Unsweetened baking chocolate and cocoa powder usually contain more than 14 mg of theobromine per gram.
• Semisweet dark chocolate and milk chocolate usually contain around 5 and 2 mg of theobromine per gram, respectively.
• White chocolate is considered an insignificant source of theobromine.

In dogs, mild clinical signs such as restlessness or excitement may appear after ingesting 20 mg/kg of theobromine and caffeine. Clinical signs such as marked hyperthermia, tachycardia, and hypertension are observed with 40-50 mg/kg, leading to seizures, tremors, muscle rigidity, and coma with 60 mg/kg.

Decontamination through emesis or gastric lavage, administration of multiple doses of activated charcoal, and meticulous supportive care should form the basis of treatment. The prognosis is usually good if effective decontamination is achieved within 2-4 hours after ingestion.

Cortonovis C., Caloni F., (2016) “Household Food Items Toxic to Dogs and Cats”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4801869/