Sophia Kansas City, Missouri 1/14/2015 9:03:22 PM Rebecca, I'm so sorry to hear about your loss. I'm no vet, but I recently took my dog to the vet due to accidental rat poisoning and have been doing a lot of research. Short answer : yes. D-con uses the chemical Brodifacoam which is highly lethal. So I'm not a vet, but my dog nearly died of a similar poisoning (Warfarin) which is not as strong as Brodifacoam. Usually, it takes 3-5 days for it to take complete effect, but if your dog ate a lot, and Brodifacoam is one of the strongest rat poisons out there, I think it's likely.Here is the link to the post I wrote about my dog's experience with rat poison: http://www.asiangirlmeetsworld. com/butler/butler-dogs-near-death-experience/Hoping that it helps somebody-- it took so long for us to find out the cause of our dog's ongoing illness (bleeding gums that wouldn't stop bleeding)- he nearly bled to death in the process.