Magnesium citrate
constipation
"I take this occasionally for really bad constipation.  This stuff works when nothing else works!  However -and this is important to note, it's uncomfortable.  As soon as I take it, I feel somewhat nauseous for several hours, and my heart rate spikes to a worrisome level.  You have to relax and force yourself to hydrate even though you won't feel like eating or drinking anything.  Because of the heart rate, it has sometimes given me insomnia too but I don't think it does that to everyone.  It is cheap & effective.  It's fizzy with a strong lemon taste and a weird aftertaste.  I agree w/ others that you should take a day off & be ready to run to the bathroom several times."