UC is so personalized that what helps one might not help another. Lialda is one of the more tolerated drugs with few side-effects for many, but others do not respond to it at all. I'm taking it, and honestly, I can't tell if it is the Lialda helping me out (which I doubt), or if it is the pred, along with the diet changes I made recently.
When your mom starts on Lialda, keep an eye on her symptoms, and if after a couple of weeks it isn't helping, let your doc know.
I'm not sure if you said, but adding a probiotic could make more difference in reducing symptoms than relying on Lialda alone. Look at member's signatures for ideas on what supplements others are taking. Most are using a probiotic, and there are quite a few of us that swear by the probios. Once you start taking one though, it is an indefinite supplement, so it'll part of the med regime for the forseeable future.
Good luck, and I hope your Mom starts feeling better soon. The first few years of dealing with UC are the hardest, because there really isn't any one solution for everyone. Keep trying until you find something that works.
36 y.o. male
Diagnosed w/ moderate UC in May '06
Meds & supplements:
Asacol, Florastor, VSL#3, Wellbutrin XL, Prozac, multi-vitamin, Allegra, Lialda, Colocort, Prednisone, flaxseed oil, L-glutamine.