Theobromine is the toxic ingredient in it. Caffine isn't good either but there's less of it. It is a stimulant, increases heart rate and blood pressure, and can cause vomiting. Larger the dose obviously the worse the effects are and can be.
On this website it shows all food poisonous and why. Pretty cool never knew turkey skin was poisonous to them. I also always wondered why chocolate was poisonous to them. I got so worried the day my dog snuck some. After that there were no bad reactions he was perfectly fine even though he only weighed two pounds.
There are many more foods beyond that list that can be poisonus. And I am doubtful turkey skin alone will cause pancreatic issues. Any large amounts of high fat foods can potentially do that, generally would be an over time thing though.
Chocolate: Chocolate contains theobromine, a compound that is a cardiac stimulant and a diuretic. When affected by an overdose of chocolate, a dog can become excited and hyperactive. Due to the diuretic effect, it may pass large volumes of urine and it will be unusually thirsty. Vomiting and diarrhea are also common. The effect of theobromine on the heart is the most dangerous effect. Theobromine will either increase the dog's heart rate or may cause the heart to beat irregularly. Death is quite possible, especially with exercise. Symptoms of chocolate poisoning include: vomiting, diarrhea, tremors, hyperactivity, irregular heartbeat and seizures.
Larger quantities of chocolate can poison or even kill a medium or large dog. An ounce or two of chocolate may not seem like much but it can be lethal to a small dog that weighs 10 lbs. or less. After their dog has eaten a large quantity of chocolate, many pet owners assume their pet is unaffected. However, the signs of sickness may not be seen for several hours, with death following within twenty-four hours. Cocoa powder and Bakers chocolate: Are the most toxic forms. These forms of chocolate contain ten times more theobromine than milk chocolate. Even licking a substantial part of the chocolate icing from a cake can make a dog sick. The next most dangerous forms are semi-sweet chocolate and dark chocolate, with milk chocolate being the least dangerous. A dog needs to eat more than a 250gm block of milk chocolate, however the high amount of fat found in milk chocolate can lead to an attack of pancreatitis.
1 ounce per pound of body weight (2 ounces per kg of body weight) for milk chocolate. 1 ounce per 3 pounds of body weight ( 1 ounce per 1.5 kg body weight) for semi-sweet chocolate 1 ounce per 9 pounds of body weight ( 1 ounce per 4 kg) for baker's chocolate.
During many holidays such as Christmas, New Year's Day, Easter and Halloween, chocolate is often accessible to curious dogs, and in some cases, people unwittingly poison their dogs by offering them chocolate as a treat or letting them lick a frosting bowl.
Here is a link to ALOT of dangerous food and plants foryou to have alookover, pictures of the items are on the page also.