Dogs can eat hazelnuts, but it is generally not recommended. Hazelnuts are not toxic to dogs, but they pose several health risks. Their small and round shape can be a choking hazard, especially for small breeds. Hazelnuts are also high in fat, which can lead to pancreatitis, a painful and potentially serious inflammation of the pancreas. Furthermore, dogs may have difficulty digesting hazelnuts, which can cause gastrointestinal problems such as vomiting, diarrhea, or constipation. There is also a risk of mold contamination in raw hazelnuts, which can be toxic. If a dog eats hazelnuts and shows symptoms like lethargy, vomiting, diarrhea, or abdominal pain, a veterinarian should be consulted immediately. For those reasons, it's safest to avoid feeding hazelnuts to dogs and opt for safer treats instead.