My name is***** and I think I can help your dog. While I do not recommend allowing a dog to eat marijuana, it is minimally toxic.
I would recommend inducing vomiting if the dog is still very awake and aware of what is going on. You can do this by forcing the dog to swallow about 2-3TBSP of hydrogen peroxide. This should reduce the amount of marijuana in the stomach my about 75-90% and minimize the likelihood that the dog will become "stoned."
If the dog is already acting "stoned," confine the dog to a crate or small room and wrap them in blankets to keep them warm. DO NOT induce vomiting in a dog that is already "stoned." A "stoned" dog will be very wobbly on her feet, weak, have either very small or very large pupils and will often be dribbling urine. They also will become very cold and cannot shiver to stay warm. The good news is that they will wake up in about 6-12 hours. You also need to watch closely for loss of consciousness, seizures or reduced breathing. If you see any of these signs, please take the dog your your local veterinary emergency clinic right away.
For the future, dogs REALLY like the taste of marijuana and will seek it out to eat it again. I recommend storing it either in the refrigerator or a cabinet that is very high up. I have seen dogs break open doors and low cabinets and a dresser drawer to get to marijuana.
Also, for future emergencies I recommend the ASPCA Animal Poison Control Center. . They are your best resource for any animal poison-related emergency, 24 hours a day, 365 days a year. If you think that your pet may have ingested a potentially poisonous substance, call (888)(###) ###-####/strong>. A $65 consultation fee may be applied to your credit card. They will ask you the name of the product as well as any listed ingredient and will tell you if the product is toxic and if you should rush your pet to the nearest veterinarian.
Best regards, ***** ***** this answer helps you. Feel free to contact me if you have any further questions.
Kansas State University
College of Veterinary Medicine Class of 2001