Another article...this month in Horse and Rider-this is about the 
  fourth I have seen in the last year stating that Psyllium does absolutely 
  nothing in getting rid of ingested sand. One of the other articles (Equus, I 
  think) stated that they have done a study  and that the horses fed 
  psyllium were compared to a control group and that the subsequent surgeries 
  showed no difference. 
The H&R article says that psyllium does not aid 
  gut motility, nor help get out the sand, but it won't hurt your horse. BTW, 
  this issue actually has a one page article by Becky Hart on Endurance. What do 
  you know, a mag that usually only has peanut rollers! 
Tiffany 
   
  *This is what Susan Garlinghouse basically has 
  said in her lectures.....you would have to give huge amounts daily for a 
  month, to make much difference.  I believe she states best things to 
  encourage gut motility; moving dirt and sand out, are exercise and 
  roughage.  Susan, hope I didn't misunderstand what you said at the 
  Western region conference a few years ago....
  Karen