我认为狗狗吃苹果会吐的原因可能是因为苹果中含有的膳食纤维太多，这就导致了狗狗的胃肠道负担增大，从而引起呕吐。另外，dog’s stomach and intestines cannot digest and absorb dietary fiber very well, so if they eat too much of it, they may experience some discomfort in their digestive system, including vomiting and diarrhea. Dogs may also vomit due to an allergic reaction to apples.

If your dog has never had apples before but vomits after eating them, you should stop feeding them apples and consult a veterinarian to check for possible allergy reasons. In general, dogs eating apples can lead to vomiting in some cases, but not all dogs will have this problem. If your dog vomits after eating an apple, you should seek medical attention immediately and avoid giving them apples again in the future.