You name it and dogs can get into it. Some dogs actually seek out things to chew, eat or destroy. Some items are generally non-toxic and other items can be highly toxic. If your pet got into something and you are not sure if it is a problem, the safest thing to do is to call your veterinarian, local emergency clinic or the ASPCA Animal Poison Control Hotline.
Toxic items that dogs may ingest include:
Grapes and raisins
Cocoa Bean Mulch
Cigarettes and cigarette butts
Rat and mouse poisons
Human medications (blood pressure medications, blood sugar medication, asthma inhalers, antidepressant drugs, aspirin, ibuprofen, and many, many more). Pretty much any medication can be dangerous depending on the dosage and the size of your dog.
Some types of chewing gum that contain Xylitol
Yarn, string, ribbon, cassette tape and other similiar items
Anything not digestible that can cause an obstruction by getting caught in the stomach or intestines