Chewing apple seeds releases a little amount of cyanide. Cyanide toxicity is rare since the seeds are most deadly when the fruit is wilted or decaying.
Alcohol harms dogs' livers and brains like it affects humans. Your dog may not drink your beer when left alone, but keep it away to avoid temptation. Given their organ size, smaller dogs may develop severe symptoms.
Persin, a fungicidal toxin in avocados, can induce diarrhea, vomiting, and even death in animals. Avocado seeds, leaves, and bark contain toxicity. Avoid giving your dog avocados if you grow them. The seed could also clog the dog's stomach or intestines if eaten.
According to the American Kennel Club, chewing bones can harm dogs but clean their teeth. "While dogs like big bones to chew on, cooked meat bones can splinter and block or lacerate the gastrointestinal tract, requiring surgery," explains Dr. Rachel Barrack of Animal Acupuncture in New York City.
The natural sugar-substitute xylitol in gum and confectionery can harm pets. The FDA says "When dogs eat something containing xylitol, the xylitol is more quickly absorbed into the bloodstream, and may result in a potent release of insulin from the pancreas." Quickly lowering blood sugar can be fatal.
Oranges, tangerines, and clementines are safe for dogs in modest amounts. But "they are high in sugars and can potentially cause GI upset if your pet eats too many of them," Barrack adds.
Although we adore chocolate, pets are at risk from it. "Chocolate contains methylxanthines such as caffeine and theobromine," Barrack adds. "Dogs are much more sensitive to these than people are."