Depends on the type of surgery. This may seem delicate,hope not to offend but really panties in a larger size are a luxury when you can't reach to pull up, when your body bloats after surgery etc. A soft gown to wear after the hospital gown is no longer required.
A pretty pillowcase.
A small pillow to protect body from seat belt and to use to sleep with, again depending upon the surgery.
Prayers for your dear friend. A prayer shawl would let her know others are praying. If you don't have time to whip one up call a local church, put her on prayer list & ask if they have a prayer shawl ministry.

How about a book or two to read? I ditto somebody's idea of chapstick. There are really fun flavors made for teenagers that she might enjoy....like Hershey's Kiss, Peppermint Patty, Jolly Rancher, that kind of thing.

Prayers for your friend.

her own pillow case-
my oldest daughter who has had 2 liver transplants + lots of other things has spent considerable time in hosp. always wants her own pillows/pillow cases and pjs: button up front and short sleeves to go over IV lines.

I like the pillowcase idea. You could make a themed one using Missouri Quilt Co.'s tutorial for the "tube case". They are quick and easy and you could do one in fabric that would be appropriate for her. Also maybe one of the neck thingies that people use on planes (you know, they wrap around your neck for comfort while sitting up) or even some audio books if she likes them. Bless you for what you are doing and prayers for her.

it is highly suggested to take clorox wipes to the hospital w/you. everything just doesn't get wiped down.It's suggested that you wipe down bedrails, phone, patient table, handles in bathroom! This will cut down on your chances of getting a staph infection(like mrsa) while at the hospital!My #1 gift, these days!

LIP BALM,,,, my lips always get dry in the hospital.

Books on tape or CD, with earphones, a special pillowcase, tablet to write questions and notes, change for the food machines for visitors, a small battery hand held fan for when she gets overheated in some of those hospital rooms, minty breath strips that melt on her tongue to freshen her dry mouth.

Lots of socks sugar free mints and a good inspirational book to have her read or be read to while waiting for surgery it really helps to take your mind off surgery and puts you in a good frame of mind and to remind you that he is in charge

Lots of socks sugar free mints and a good inspirational book to have her read or be read to while waiting for surgery it really helps to take your mind off surgery and puts you in a good frame of mind and to remind you that he is in charge