Human Foods You Should Never Feed Your Pet

Chocolates, Coffee and Caffeine
Cacao seeds contain a substance called methylxanthines which, when ingested by pets, can cause diarrhea, vomiting, panting, urination, excessive thirst, tremors, abnormal heart rhythm, hyperactivity, seizures, and even death.   Thus, you should never feed your pet any product that contains cacao or caffeine as a major ingredient including chocolates, coffee, and coca sodas.  Take note that dark chocolates contain more cacao than milk chocolate and that white chocolate has the lowest level of methylxanthines.  Baking chocolate has the highest level of methylxanthines.

Avocado
Avocado fruit, including its leaves, seeds and bark contain Persin, an ingredient that can cause diarrhea and vomiting in dogs. Rodents and birds are also very sensitive to avocado poisoning, the ingestion of which can cause difficulty of breathing, congestion, and fluid accumulation around the heart.  In some cases, avocado poisoning may be fatal to these pets.

Macadamia Nuts
Macadamia nuts, while delicious for humans especially when used in candies and cookies, can be very dangerous for dogs. Macadamia nuts have been known to cause vomiting, tremors, weakness, hyperthermia, and depression in dogs.  The symptoms can appear within 12 hours of eating macadamia nuts and can last for as long as 12 to 48 hours.     
Raisins, Prunes and Grapes

Raisins, prunes, grapes and other similar fruits have known to cause kidney failure in animals, especially those with certain health problems. However, the toxic substances in these fruits are unknown.   

Source : articlesbase