First of all, welcome to HealingWell. I'm sorry your daughter has UC, but glad you found us and hope this forum will be helpful to you.
In my own personal experience, Remicade has been much more gentle to my body than steroids were. I've been on it for two years with no adverse effects. The side effect most people worry about is the small increased incidence of lymphoma. This occurred in a tiny number of cases, and all of the people were taking Remicade and immunosuppressants such as Imuran at the same time.
That said, there are other things that can be tried before Remicade if your daughter wishes to do so. I wasn't able to take Asacol because it made my symptoms much worse, but Colazal helped me. There are the immunosuppressant drugs. The sad thing is that all medications have some undesirable side effects, yes, even "natural" ones. So we have to weigh the risks against the potential benefits.
You'll get a lot of suggestions here; just remember that each of us is different and what works for some doesn't work for others. We each have had to sort out our own best regimen for optimal results.
There is a lot of hope, though. Getting that remission can be tough. I was really sick for quite a while. Now I live normally, eat normally and only occasionally even need to think about having UC. Hopefully your daughter will respond to treatment soon so she can go on with her own life. She's very lucky to have a supportive mom like you!