We have all heard of many different things that are toxic to dogs, but they are all kind of rumored. I am here to put those rumors to rest and to state what is, and isn't toxic to dogs. Also, what to do if your dog does eat something toxic.
Things that are toxic to dogs: Avocado, raisins, grapes, onions, garlic, walnuts, macadamias, mushrooms, caffeine, xilitol (found in gum and candy), any human medication (including tylenal & advil), any processed fatty foods (fast food), Dark Chocolate (a little milk chocolate is fine, don't freak out if your dog eats a hersheys bar), cooked bones (not toxic but can break up and cause cuts inside their throat or stomach).
These things are toxic, so don't feed them to your dog.
If your dog does get into these things and by a large amount, no need to go to the vet and get their stomach pumped, it will be very expensive and very hard on the dog. Simply get some Hydrogen Peroxide and pour some down their throat. They will not drink this on their own so you'll have to hold their mouth up and open and pour it on down. The dog will most likely throw up very quickly, but don't be fooled, they aren't done yet. Keep them outside for about 30-45 minutes, they will throw up a few times more. I've had to do this a few times when dogs got into pain meds and vitimins.
If your dog is in pain for some reason, do not give them human pain killers or ibuprofen of any sort, they need dog pain killers only obtained from a vet.
People out there often want to give their dogs some snacks, so here are a few things that is ok to give to your dog, but not in excess. Lean and unprocessed meats (raw or cooked), peanut butter, and rawhides. I know this is not an extensive list, but thats about it when it comes to healthy dog snacks that aren't bought in the pet store. Raw hides are good to clean their teeth but a little hard on their stomachs (gives them bad gas) so I give all my dogs one rawhide about once a month to keep their teeth healthy and not to have bad breath.
Just know that things made for people aren't made for dogs. People food can easily make them sick and can be toxic. Love your dog enough to tell them no.