I heard that foods such as onions and chocolate can make dogs sick. Is this true?

Some foods that are edible for humans can pose hazards for dogs because of the difference in metabolism. Some may cause only mild digestive upsets, whereas others can cause severe illness and even death. The following common food items should not be fed to dogs. This list is incomplete, but does cover many common food items found in homes.

Onions and garlic contain the toxic ingredient thiosulphate, although onions are more dangerous. Both can trigger a form of anemia where the body's red blood cells burst. This results in poor oxygen supply to vital organs and tissues. Serious and potentially deadly nutritional deficiencies may result if consumed regularly. Chocolate contains compounds known as methylxanthines, which dogs are sensitive to, causing hyperactivity, increased heart rate, tremors. It is potentially fatal. The amount of toxin in chocolate depends on the type, but the general rule is the more bitter, the more toxic.

Coffee, coffee grounds, tea, soft drinks can cause caffeine toxicity, which over-stimulates the central nervous and cardiovascular systems, while grapes and raisins contain an unknown substance that can cause kidney failure in dogs. Most fruit pits and seeds contain cyanogenic glycosides, which cause cyanide poisoning, resulting in vomiting, lethargy and excessive drooling, although the fruit itself is OK. Macadamia nuts contain an unknown toxin that can affect the digestive, muscular and nervous systems, and nutmeg can cause tremors, seizures and central nervous system damage.

Most bones should not be given because they can splinter and cause lacerations to the digestive tract or become lodged in your pet's throat, posing a choking hazard. Potatoes and rhubarb contain a substance called oxalate, which triggers life-threatening abnormalities with the nervous system, kidneys and digestive tract. Especially toxic are green tomatoes, green potatoes, potato skins, and tomato leaves and plants. Rising bread dough can be life threatening because your pet's body heat will cause the dough to rise in the stomach, producing gas and expanding to several times its original size.

Need advice from METRO's pet expert? E-mail your questions to metrobeijing@chinadaily.com.cn. Please give as many details about your situation as possible. Answers supplied by the International Center for Veterinary Services in Chaoyang district, 8456-1939, icvsasia.com.

China Daily

(China Daily 05/31/2011)