My appologies for assuming it was your Dane that ate the chocolate, you mentioned them in the previous paragraph so I thought you were speaking about the same dog, when you just referred to them as "my dog". I would still stand by what I said about chocolate in general. Just because your dog got off unscathed, which I am pleased to hear, but this does not necessarily mean all dogs would.
The seeds in an apple contain low doses of cyanide. And in high quantity can poison a dog. (But people are affected the same way)
Dogs can get vitamin C toxicity. Unlike humans, a dog's body manufactures citric acid on its own.
Indeed a dog produce their own vitamin C naturally. A healthy dog will produce around 18 mg per day, per pound. This means that a 60 pound dog will produce more than 1000 mg on their own each day. Apples on the other hand contain about 7-10 mg of Vitamin C each. You'd have to feed a dog a lot of apples before it became toxic. You probably shouldn't make a habit out of it giving them multiple apples per day everyday, but giving your dog an occasional apple shouldn't do them any harm at all.
