<unk> (oral, topical) is a saline laxative that is FDA approved for the treatment of occasional constipation (irregularity).   Common adverse reactions include flushing, sweating, hypotension, depressed reflexes, flaccid paralysis, hypothermia..
Magnesium sulfate 
Magnesium chloride
Magnesium gluconate
Magnesium levulinate
Chloral hydrate
Benzonatate
Magnesium lactate
Magnesium carbonate