Is "people food" safe for dogs? Some is, some isn't, and knowing what's OK to share can mean the difference between a healthy treat and a trip to the emergency clinic.

• Sugar-free candy and gum: Read the label of your favorite sugar-free gum, candy or even cough drop, and you'll likely find xylitol on the ingredients list. The sweetener has become extremely popular in recent years, and its increased use has led to many cases of poisoning in dogs. The product causes low blood sugar and liver failure in canines. If you carry sugar-free gum or candy in your purse or backpack, make sure you keep it out of reach of your pet.

• Chocolate: Though xylitol's toxicity comes as a surprise to many people, pretty much everyone knows that chocolate can be a problem for dogs. And it is, but it's not as dangerous as most people think. The thing to remember: The darker the chocolate and the smaller the dog, the more dangerous the combination. If your Labrador retriever eats a small bar of milk chocolate, she'll likely get only a bellyache. But a tiny Maltese who eats a few ounces of dark chocolate could land in the emergency clinic.

• Raisins and grapes: No one really knows why grapes and their dried relations, raisins, are a problem for dogs, but they surely are. Dogs who eat a large amount of either may go into renal failure. It may be that some dogs are sensitive and others are less sensitive, and it's unknown if small amounts over time can be as dangerous as one large bunch of grapes or raisins. Due to the uncertainty, the ASPCA's Animal Poison Control Center advises against giving any amount of raisins or grapes to any dog at any time.

• Macadamia nuts: Another medical mystery, these nuts are best not shared with your pets -- especially if they are cloaked in dark chocolate. Though fatalities are rare, as few as 10 nuts can cause frightening symptoms in a small dog, such as muscle weakness, tremors and vomiting. It's just not worth it.

• Onions and garlic: Garlic and onions can damage healthy red blood cells, leading to life-threatening anemia if not caught and treated in time. Final note: Veterinarians often recommend that ill pets who won't eat be tempted with meat-variety baby food. But be careful to read the label, as some baby foods contain garlic and onions. Choose a brand without them.

Now that I've told you what you can't share with your dog, I'm happy to share my favorite treats that you both can eat. Some words of warning first:

Treats count as food. More than half the nation's pets are overweight or obese. So while it's OK, in general, to share healthy food with your pet, watch the size of the treats (break them up – dogs can count, but they can't measure) and the frequency.

Treats also can lead to behavior problems. If you give your pet a treat whenever he asks, be prepared for him to ask often – and to issue a demand when a polite request doesn't bring forth the goodies. Make sure every treat you give is on your terms, not your dog's. Even better: Use treats for training, which means you'll be working toward a goal when the goodies come out.

So what kinds of people food are good for sharing? My favorites are baby carrots and apple slices. I also like sharing blueberries, yogurt and lean bits of meat, such as baked or boiled chicken with the fatty skin removed. When in doubt, ask your veterinarian if a particular food is safe for your pet.

The bottom line: A little sharing can be OK. Just know what's safe for your pet and make sure you're not either helping your dog pack on the pounds or learn tricks you'd rather he not.

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Pet Connection is produced by a team of pet-care experts headed by veterinarian Dr. Marty Becker and journalist Gina Spadafori. The two are also the authors of several best-selling pet-care books. Email them at petconnection@gmail.com or visit www.petconnection.com. Back columns: www.sacbee.com/spadafori.

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