I would avoid any scented lotions= nearby patients may have a scent intolerance. I would also avoid any nail polishes= medical staff use the natural color of the nail bed to determine health problems. I would also avoid bringing blankets and sheets= they tend to get "lost" in a hospital environment. Food should also be a restricted or limited unless you know of the true condition of the patient. Consider...a nice card, reading material, a tooth brush, a hair brush, a small mirror, maybe an assortment of teas, warm socks. Practical things are always best. The best gift is to ask " What can I bring you, what do you need ? " .
How old are they? Think about what they're there for and what all they can do. If they're on bed rest, then you can bring them reading material or activity books. If it's a kid, you can bring toys that they like. If it's an adult, you can bring books, like I said earlier, or something to keep them occupied. Puzzles are a great one for any age.