What is your italian greyhound's weight? (the smaller the dog, the less chocolate needed to poison). When did your dog eat the chocolate?
It's theobromine in chocolate that is toxic to dogs. If your dog has previously been diagnosed with epilepsy, it's especially harmful and you should get the dog to the vet right away.
Theobromine toxicity is measured on a mg per kg basis. Baking chocolate, bitter, bittersweet, dark and cocoa powder chocolate are among the worst with between 150 to 600 mg theobromine per ounce. Milk chocolate is about 45 to 66 mg per ounce. It would take an ounce of milk chocolate or semi-sweet per 1 lb of body weight to poison a dog. That means for a 10 lb dog, 10 ounces of milk chocolate (a typical Hershey bar is about 1.4 ounces so we're talking 7 candy bars) would poison the dog. For sweet cocoa it would take 0.3 ounces per 1 lb of weight to poison and for baking chocolate it would take 0.1 ounce per lb to poison. Thus, around 2.6 ounces of sweet cocoa or just a one square of bakers chocolate eaten by a 10 lb dog requires medical intervention. Thus, I would highly recommend that since Italian greyhounds are small that you keep your dog calm and get him to your veterinarian.
The smaller the dog and the higher the theobromine level, the more dangerous it is in a shorter period of time. There will be anything from heart irregularities, vomiting, seizures, tremors, diarrhea to complications up to 4 days later that are the result of liver malfunction or internal bleeding caused by the theobromine. Thus, if you believe that your dog is experiencing actual poisoning from the chocolate itself (meaning the dog ate the chocolate over 2 hours ago and did not vomit it up), keep him calm and inactive and get him to your vet.
I would usually tell a dog owner to induce vomiting to get the chocolate out of his system if the chocolate was ingested within the last two hours. Since your dog is already vomiting frequently, I do not think that you need to induce vomiting at this point. Did your dog start to vomit within two hours after eating the chocolate? or was it later than two hours? (I will include the instructions to induce vomiting at the end of this answer in case you need it in the future - it's good to keep the instructions handy).
Hopefully your dog started vomiting within two hours of eating the chocolate and got the chocolate out of his system. The foil wrappers could have been irritating enough also to cause your dog to vomit. Usually the foil wrappers would pass through and not cause any blockage (the foil wrappers on chocolate easter eggs tend to be quite thin foil).
What substance has your dog been vomiting - can you see the chocolate and foil in your dog's vomit? If so, that's good that your dog is getting that out of his system.
After your dog has finished vomiting, you can administer activated charcoal. If you do not have activated charcoal, thoroughly burn some toast so it's black and then crumble it up and give your dog several slices. The activated charcoal binds the remaining theobromine in your dog's system and should harmlessly remove it through the feces. If using activated charcoal, mix it with water until a milkshake consistency and offer 1 teaspoon to dogs under 25 lbs; 2 teaspoons for over dogs more than that.
For additional information, check out http://www.marvistavet.com/html/body_chocolate_toxicity.html
To be certain, as I stated previously, I would get your dog to your veterinarian. Or you could, contact the Pet Poison Helpline at 1-800-213-6680 or the Animal Poison Hotline at XXX-XXX-XXXX or XXX-XXX-XXXX - http://www.aspca.org/apcc (not free services, but can save the life of a poisoned dog).
Hope your dog does okay and gets better!
How to induce vomiting (should you need this in the future):
If the dog ate something poison in the last two hours, you can induce vomiting to get the substance out of your dog's system (it's best to do this in an easy-to-clean area, i.e. one with a tile floor). To induce vomiting, do one of the four procedures listed below (note: never induce vomiting if the substance swallowed is corrosive or caustic because it will also burn on the way back up - i.e. household cleaners, drain cleaner, petroleum-based products, etc. Also, if your dog is having trouble breathing, having seizures, has a slow heart rate, is unconscious, or has a bloated stomach, never induce vomiting):
1.Give syrup of ipecac (1 teaspoonful per 10 lbs of body wt)
2. Give one teaspoon of 3% hydrogen peroxide for each ten pounds of body weight. Or you can give 1 to 3 teaspoonfuls (depending on your dog's weight) every 10 minutes and repeat three times, but not more than three times. This should quickly induce vomiting.
3. If you don't have access to #1 or #2, try a combination of one tablespoon of dry mustard and one cup of cold water.
4. If you don't have access to #1, #2, or #3, place one-half to one teaspoonful of salt at the back of your dogs tongue.
Certified Pet Dog Trainer
16 years experience as a pet dog trainer. AKC titles in obedience, tracking, field and agility.