Magnesium citrate
"I recently changed my diet and have been eating more protein which has seriously backed me up.  I hadnt pooped for 4 days and felt nauseous after eating and bloated and gassy.  My stomach was rock hard with no relief from senna, essential lemon oil, digestive enzymes, probiotics, colon cleanse, and smooth move tea.

A friend recommended mag citrate.  I had never heard of it before.  Went to store and bought it for 1.99.  Sour Lemon taste.  I drank half a bottle and nothing.  Drank the other half and 16 ounces of water (maybe more) and the magic started happening.  I'm still sitting on the toilet with my pants around my ankles hoping for some more movement.  

This stuff works.  Be patient.  It took me 1.5-2 hours for the first movement."