I am a long-time owner of cribbers and currently have two. One has been with me for 16 years (he's now 20) and was a cribber when he was given to me. The other I've had for three years, she was also a cribber when I bought her (can you tell I'm not worried about it? Heh.)
Corymbia's post is very good and pretty much covers the current state of knowledge on cribbing (I've done a fair amount of research myself over the past 16 years...).
It's true that you can't really 'cure' a horse of cribbing unfortunately (for the reasons Corymbia already explained). Best thing you can do for the horse is manage it accordingly. In other words, make her more comfortable. It's true that most cribbers pick up the habit because of gastrointestinal problems (high levels of stomach acid and/or ulcers, these are related). These are usually caused by keeping/feeding the horse in a manner that goes against the nature of the horse.
Here's what I would do (and did with mine) to reduce the cribbing. Just my 2c so you can take it at face value
1) Turn the horse out as much as possible, preferably to pasture. If she can't have grass all day, dry lot works.
2) Make sure she always has something to eat. Grass hay of the longer, stemmy kind works best (if you don't have access to pasture). The point isn't so much to get a bunch of nutrients in her, but to keep her system 'busy' and her stomach full.
3) Avoid large portions of grain. These work like a 'bomb' on her system and will trigger more cribbing. If the horse has a hard time keeping weight on with just pasture or hay, or needs supplements, try soaked alfalfa/timothy cubes with an oil (fat) supplement.
4) Check for ulcers. Cheapest way to do this (without having to scope or start with omeprazole meds, both of which are crazy expensive) is to go to Walmart and get a large bottle of the 1000mg tums. A bottle of those, Walmart brand, is about $4.-. Give the horse 10 of these a few times a day, either from the hand or in her feed and see if this reduces the cribbing. Or if the horse has a tendency to be girthy or sensitive around his barrel, see if this gets better after a few days. If any of those improve, you have a gastrointestinal problem that is contributing to the cribbing. (if this is the case, there's adjustments you can make to her feed that will help him heal. You can pm me for a link)
Finally, some additional thoughts:
5) Do not use collars. Just don't. They don't work, horses will figure out a way around/through them. They cause damage, I've seen too many horses with sores, permanent indentations of the throatlatch, damage to vocal cords, etc.
6) Let her crib. Yup, just like Corymbia said: they do it for a reason and making it impossible without addressing the possible cause first is cruel. No, she won't colic from the cribbing. The air they appear to suck in hardly ever makes it to the stomach. It lingers in the esophagus and is burped back up. The cribbing itself is not what causes colic in cribbers, it's the underlying gastrointestinal problems.
This turned into a really long post, sorry... Good luck with her, if you try the things above she should at least ease up on the cribbing and stay happy.
Edited because I just figured out your horse is a she and not a he