Folks often ask me if this-or-that food is okay for pets. I like to tell them all people foods are "toxic" to animals, since even moderate quantities can lead to a chronic condition proven to shorten lifespans and known colloquially as FAT, or Food-Amplified Tissue syndrome. You can read more about that in this article. Furthermore, anyone whose Lab has ever raided the trash can can tell you that enough of anything a pet isn't used to eating can result in a few days of sickness (and maybe a visit from the carpet cleaners). Of course, some things in the kitchen can harm your pet much more quickly and severely, and today's article covers the four biggest culprits.
Lets start with a few general notes. First off, if you are concerned about something Muffy indiscriminately scarfed down the first thing to do is call your vet. If they aren't open, try the nearest pet emergency hospital or Animal Poison Control. They can tell you if you should freak out, how much you should freak out, and what you should do next (after they get you to stop freaking out). The risk is usually going to depend on how much toxin went into how much dog; that is, a nibble of onion or milk chocolate probably won't faze a Great Dane, but it could be enough to kill your 2-pound chihuahua. Cats also tend to be more sensitive to most toxins, food or otherwise.
Onions and Garlic
Plants in these families contain sulfur compounds that can damage red blood cells, causing them to rupture. Since red blood cells are responsible for carrying oxygen to the body's cells, and those cells need oxygen, this is kind of bad. Common signs logically include weakness and pale gums; however, these problems occur hours to days after exposure. Note that garlic and onion powders are just as dangerous, and may be used in processed human foods in significant portions - just one more reason to keep pets out of the people food!
Grapes and Raisins
These can trash your pet's kidneys. Kidneys are rather important. Raisins are more potent in this regard, which shouldn't be surprising since they are basically grapes minus the water - and water, at least, is good for kidneys.
Before anyone asks -yes, some dogs and cats seem to tolerate grapes and raisins just fine, and we aren't sure exactly what the mechanism for the toxicity is in the first place. On the other hand, some pets die from eating these. Just keep them out of them, okay?
Cocoa contains stimulants that are very dangerous for pets. Early signs include vomiting and diarrhea, leading to extreme excitement and agitation (imagine your chihuahua on three cups of espresso), and even death.
But wait - a culinary lesson! Chocolate is a blend of sugar, fats, and cocoa; the amount of these determines the type, flavor, and quality of the chocolate. Milk chocolate has little actual cocoa, dark has a good bit, and semi-sweet or baker's chocolate is mostly cocoa. This is important because the more cocoa, the more danger for your pet. White chocolate is made with cocoa butter rather than actual cocoa powder, and so is fairly harmless unless they try to eat their weight. How much is too much? Check out this excellent interactive chart from National Geographic. But remember, each dog is different - contact your vet if you are worried!
Xylitol (that's a sweetener, not a Russian side dish)
This is present in many sugar-free gums, mints, vitamins and even toothpaste. Within 30 minutes of ingestion it may cause a dog's blood sugar to drop to dangerous levels, resulting in seizures, coma, or death. Worse yet, even if they don't show these signs some dogs may develop liver failure hours to days later. Because of this overnight hospitalization and monitoring is advisable in most cases.
Lastly, this list is not exhaustive. These are the most common and dangerous food items; other things like macadamia nuts, avocados, and fruit seeds may be harmful as well. APC has a nicequestion-and-answer list covering the good, bad, and mostly-harmless foods folks often ask about. But definately keep Muffy out of your stash of sugar-free, chocolate covered raisins dusted in onion powder! You can send me some, though. That sounds tasty.