Sodium citrate/sodium lauryl sulfoacetate/glycerol sold under the brandname Microlax and Micolette Micro enema, among others, is a small tube of liquid gel that is used to treat constipation.
active ingredients are sodium lauryl sulfoacetate (0.90% w/v), sodium citrate (9.0% w/v) and glycerol.
The main use is for treatment of
constipation. In surgery it is used for pre-operative evacuation of the bowel. In  diagnostic testing it is used before x-ray examinations or physical examinations of the colon.
It has no age limits in regards to children and can be used safely.
If used in children under 3 years it is recommended that the  nozzle is only inserted half way. It is suggested as a laxative during postnatal period  and it is compatible with  breastfeeding
Microlax (like any other saline laxative) should not be used in cases of intestinal inflammation.
Mechanism of action
saline is one of the most effective osmotic laxatives (secondary in action only to magnesium citrate). Its laxative action is the result of  osmotic imbalance that extracts bound water from stool and pulls it back into the large bowel. The increased water content softens the stool and stimulates the bowel to contract (move its contents to the rectum).
Sodium lauryl sulfoacetate improves the wetting and penetrating abilities of the solution, sorbitol enhances the water-releasing effect of sodium citrate and
glycerol helps to lubricate the stool. The combined action helps to soften hard stools and relieve constipation without straining in a very short period of time ~ 15 min.
The ingredients are not absorbed, distributed or metabolised by the human body, all of the composition is being excreted in
1960 - Microlax micro-enema was invented in
Sweden by Paul Gunnar Embring from Uppsala and Per Ove Mattsson from Stockholm for Pharmacia company. The original purpose of the invention was for clearing the  colon and rectum for X-ray investigation "without any risk of the fluid balance of the body being disturbed".
The first use of "Microlax" in commerce was registered in June 16, 1960.
In 1962, Microlax registered as the US trademark in February 20, 1962. 
In May 1963 first medical article on Microlax published in
Danish medical journal ( Ugeskrift for Læger Weekly Journal for Physicians).
In 1964, Microenema containing
sodium citrate, sodium laurylsulphoacetate and sorbitol was tested in preparation of the bowel for sigmoidoscopy. Results were published in the American Journal of Proctology. In 1965 a comparative study of Microlax and  enema published in Ugeskrift for Læger. In 1967 - an article, published in  proved the results of 1964 US study and confirmed the efficiency of using Microlax as part of preparation for The Medical Journal of Australia sigmoidoscopy. In 1996 a study in the  suggestedmailing "Microlax" micro-enemas to patients who are scheduled for Journal of the Royal Society of Medicine sigmoidoscopy.
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W. Lieberman (1964). "Rapid patient preparation for sigmoidoscopy by microenema". American Journal of Proctology. 15: 138–41. PMID 14139893.
J. Reimers; M. Knoth (1965). "Preparation for recto-sigmoidoscopy. A comparative study of Microlax and enemata". . Ugeskrift for Læger 127 (35): 1082–4. PMID 5829676.
Hughes L.E. (1967). "The use of a micro-enema as preparation for sigmoidoscopy". . The Medical Journal of Australia 2 (5): 215–7. PMID 6057897.
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