'Donut', this 1.5-year-old hamster came to see us with bloody vaginal discharge or bloody urine. The origin of the blood can be challenging to determine in these tiny rodents. The physical examination revealed a large, 4 cm diameter mass in her belly. We suspected that she might have a bleeding tumour in her uterus, but a tumour in the bladder could cause similar clinical signs too. Due to the constant bleeding, we recommended a diagnostic workup immediately followed by surgery to remove the mass. In order to identify the origin of the mass and to look for metastasis, we performed a contrast-enhanced CT scan. Giving contrast injections into the veins of hamsters is very challenging due to their size. Luckily, Donut was a big girl (190g), so we managed to give her the contrast material intravenously. The CT scan didn't find any metastasis, so we proceeded with the surgery. Every minute counts when dealing with tiny exotic patients because they can deteriorate very quickly. Donut was presented for the consultation at 10am; we did the CT at noon and successfully finished the surgery at 4pm on the same day.