National Health Service officials say the ban makes sense because vase water may harbor dangerous bugs, bouquets can trigger allergies and spilled water can damage equipment, Scotland on Sunday reported.
A spokeswoman for Shetland Health Board confirmed its policy of allowing flowers in its two hospitals was being reviewed.
"It is possible there will be a move to restrict all flowers for infection control reasons and for health and safety reasons, given the large amount of electrical equipment positioned around beds," she was quoted as saying.
Meanwhile, Liz Moore, healthcare director at NHS Ayrshire and Arran, said flowers were no longer allowed in some wards.
"This is due to limited space as these areas have lots of high-tech equipment and the potential irritation flowers may cause to patients in respiratory wards," she said.
Even so, microbiologist Hugh Pennington said banning flowers was unnecessary.
"There is no risk in people bringing flowers," he said. "They are therapeutic for the patient."