* It has recently been confirmed that grapes and raisins can cause acute renal failure in dogs. The exact mechanism is not known, nor any means to determine the susceptibility of an individual dog. While as little as one raisin can be fatal to a susceptible ten pound dog, many other dogs have eaten as much as a pound of grapes or raisins at a time 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. A drunk dog displays behavior pretty much analogous to that of an intoxicated person. (However, beer presents another problem; see below.)
    * Hops, the plant used to make common beer, can cause malignant hyperthermia in dogs, usually with fatal results. Certain breeds, such as Greyhounds, seem particularly sensitive to hop toxicity, but hops should be kept away from all dogs. Even small amounts of hops can trigger a potentially deadly reaction, even if the hops are "spent" after use in brewing.
    * Some dogs have food allergies much as humans do; this is particular to the dog and not characteristic of the species as a whole. An example is a dog vomiting whenever he eats salmon; many humans likewise have seafood allergies.