Corn silk or MMR for urinary issues?

Has anyone on here tried Corn silk or Marsh mallow root for  urinary issues?

Did it work?

My cat has chronic FLUTD with no crystals. I've heard online that corn silk or MMR is supposed to be helpful. I just hate to try it without any clinical studies showing it works or is even safe in cats.

How long do you keep them on it, if it works?

The Yahoo FLUTD group really recommends either corn silk or MMR for bladder inflammation. Corn silk is easier to use because you can add it to food and seems to be well tolerated by most cats. MMR needs to be given away from food, so it's harder to use. A lot of people in that group have used corn silk safely. If you join that group, I remember that there were some safety studies published a while ago. Most say that corn silk takes up to a month to start working, but it is very helpful for cases of idiopathic cystitis.

I don't really trust yahoo groups, which is why I am posting here.  There is another group I joined which is using the yahoo group to market their herbal products - they have 2 different herbal companies, so it appears they are non-biased, but when you look them up, both companies are owned by the same person! 

I was wondering if anyone on this forum has tried the herbs and had any results?