While we are sometimes tempted to feed our pets the same food we eat, here are some foods commonly enjoyed by humans that are dangerous to dogs:

• Dogs like the flavor of chocolate, but chocolate in sufficient doses is lethally toxic to dogs (and horses and possibly cats). Chocolate contains theobromine, a chemical stimulant that, together with caffeine and theophylline, belongs to the group of methylxanthine alkaloids. Dogs are unable to metabolize theobromine effectively. If they eat chocolate, the theobromine can remain in their bloodstreams for up to 20 hours, and these animals may experience racing heartbeats, hallucinations, severe diarrhea, epileptic seizures, heart attacks, internal bleeding, and eventually death. A chocolate candy bar can be sufficient to make a small dog extremely ill or even kill it. In case of accidental intake of chocolate by a dog, contact a veterinarian or animal poison control immediately; it is commonly recommended to induce vomiting within two hours of ingestion.

Note: Carob treats are often available as dog treats; these are unrelated to chocolate and are safe.

• Grapes and raisins can cause acute renal failure in dogs. The exact mechanism is not known. As little as one raisin can be fatal to a ten pound dog and other dogs have eaten as much as a pound of grapes or raisins without ill effects. The dog usually vomits a few hours after consumption and begins showing signs of renal failure three to five days later.
   
• Onions and to a significantly lesser extent garlic contain thiosulfate which causes hemolytic anemia in dogs (and cats). Thiosulfate levels are not affected by cooking or processing. Small puppies have died of hemolytic anemia after being fed baby food containing onion powder. Occasional exposure to small amounts is usually not a problem, but continuous exposure to even small amounts can be a serious threat.
   
• Macadamia nuts can cause stiffness, tremors, hyperthermia, and abdominal pain. The exact mechanism is not known. Most dogs recover with supportive care when the source of exposure is removed.
   
• Alcoholic beverages pose much the same temptation and hazard to dogs as to humans.

For more information, contact your veterinarian or the ASPCA Animal Poison Control Center