Magnesium citrate is a saline laxative used to flush stool from the intestines before colonoscopies, surgeries and other bowel procedures, as stated by WebMD. It may also be used for occasional constipation relief.
Magnesium citrate is believed to work by drawing fluid into the small intestine, according to WebMD. Milder medications, such as bulk-forming laxatives and stool softeners, are preferable for most cases of constipation. Magnesium citrate should never be used for extended periods, as this may cause laxative dependency. Users generally experience a bowel movement with 30 minutes to three hours of taking magnesium citrate. Individuals taking the medication in preparation for a surgery or other procedure should follow the doctor's instructions about when to begin taking it. Dosage varies based on factors such as age and medical condition, and users should drink a full glass of water after taking the appropriate dose.
Common side effects of magnesium citrate include gas, nausea and mild abdominal cramps, as noted by WebMD. Users should contact a doctor immediately if these side effects do not go away or worsen over time. Uncommon but serious side effects such as persistent diarrhea, mood changes, irregular heartbeat and severe abdominal pain can occur if the dosage is too high or if the laxative is taken for extended periods.