A trip to the laxative section of any drug store may be a little daunting. There are so many choices, where do you even start? There are bulk laxatives, osmotic laxatives, stool softeners, and stimulant laxatives, all of which come in various forms, ranging from pills to suppositories. However, if you’ve got a truly serious case of constipation, the main question you might be wondering is – what is the strongest laxative?
Strongest Laxative by Prescription: Sodium Phosphate
This is the most powerful code red laxative that a person can take. Sodium phosphate is used to completely empty out a person’s large intestine before surgery or so that a doctor can get a clear view of the colon walls during a colonoscopy. The chemical is usually taken in tablet form the night before surgery and will cause diarrhea until the colon is completely empty. Sodium phosphate will continue to cause bowel movements after you have stopped taking the medication and it is usually advised that you stay near a toilet during this time. Sodium phosphate might best be described by the extreme, laxative reaction scene you might have seen in the movie, “Dumb and Dumber.” 
Strongest Laxative Available OTC: Magnesium Citrate
This is another chemical that is used to completely empty the colon before surgery. Magnesium citrate is commonly known as a saline laxative, and is usually taken in pill form the night before a surgery. Although the chemical is available over-the-counter without a prescription, extreme care must be exercised when using magnesium citrate as it works by attracting water through the tissues into the intestine to help produce a bowel movement. Dehydration is a concern to many as diarrhea lasting as long as 12 hours can be expected. Other dangerous side effects include the loss of normal bowel movement routine, nausea, abdominal pain and cramping, and bloating. A rare side effect is high-magnesium blood levels, which can cause dizziness and lightheadedness. 
Saline laxatives are a strong laxative, but aren’t quite as intense as magnesium citrate. These laxatives are a quick remedy for constipation, but also can cause diarrhea and should not be taken regularly as laxative dependency is a risk you should heed. A life with an excretory system that doesn’t work properly can be very frustrating.
Do You Really Want a Bomb to Go Off in Your Colon?
Severe constipation can be very debilitating and it’s not surprising that many people equate “strongest” with “best,” especially if they’ve been disappointed previously by laxatives that didn’t provide relief. Take a step back though, you may want relief, but do you really want the extreme results of the world’s strongest laxatives? Candidly speaking, it’s not going to be a pleasant experience. Furthermore, many people suffering from even the most severe constipation have gotten quick and effective relief with far more gentle products. Using any chemical laxative is a step-up in strength from trying natural remedies and should be done with care and caution.
-Dr. Edward F. Group III, DC, ND, DACBN, DABFM
- Medline Plus. Sodium Phosphate. (last accessed 2013-05-31).
- Office of Dietary Supplements. Dietary Supplement Fact Sheet: Magnesium. (last accessed 2013-05-31).