White chocolate contains theobromine, a substance harmful to dogs. It’s the least toxic among chocolates due to lower theobromine content, but consumption can still lead to issues. As a professional, I strongly advise against letting dogs eat any chocolate, including white chocolate. The harmful effects vary based on a dog’s size and the amount ingested. In my experience, small quantities might cause symptoms like vomiting or diarrhea, while larger amounts could lead to more severe conditions such as increased heart rate, seizures, or even death. Any consumption warrants immediate veterinary attention, ensuring your furry friend’s well-being.