Most symptoms will clear up within a few days of taking D-Mannose continuously but it is advisable to take it for a little longer to make sure. For some who had repeated bladder infections over a longer period of time, we find it helpful to take D-Mannose per day to remain free of infection. This is particularly helpful for those who are susceptible to urinary tract infections such as those with spinal injuries, multiple sclerosis, chronic constipation and any condition where the bladder becomes compressed. ***