I have used it in the past and I believe it was a couple of days. Have you modified their diet at all while they have the runs? I used to give plain white rice instead of kibble but really only in dire situations.
What worked for me was pumpkin. The plain pumpkin not the pie filling and I would put the remaining pumpkin in ice cubes trays in the freezer for next time so you don't waste the whole can. Pumpkin works in both situations where your dog may be constipated it helps that way as well. Make sure they stay hydrated as well.
Tabitha April 10, 1995 - August 23, 2013
Bomber April 10, 1995 - July 12, 2010
Winston Nov 15, 1999 - September 15, 2011
Sophie Aug 30, 2011
"UNTIL ONE HAS LOVED AN ANIMAL, PART OF THEIR SOUL REMAINS UNAWAKENED"
He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours, faithful and true, to the last beat of his heart. You owe it to him to be worthy of such devotion.