Bowel Preparation before Surgery

When surgeries or procedures are performed in the bowels, the surgeons expect the region to be completely devoid of fecal matter and food residues. This would be vital in many aspects including prevention of contamination, improved wound healing, good visibility…etc. The elimination of fecal matter from the bowels and clearing up the area for a clean surgery is known as ‘bowel preparation’.

There are several ways in which the bowels can be prepared before a surgical procedure. These methods will promote a laxative effect either mechanically or functionally.

The following are some of the methods that are being used to prepare bowels either for surgery or else for endoscopic or other such procedures.

Low residue diets

Although practiced less and less in the modern day, the adherence to a low residue or low fiber diet, will prevent the build up of fecal matter which will be difficult to expel using a simple enema or an oral laxative. The general guidelines will be to stay on a low residue or low fiber diet for 48 hours and in the last 24 hours to only take clear liquids.


It is common practice to keep the patients fasting for at least 6 – 8 hours before a bowel surgery and to allow only liquids for the 12 – 24 hours before the fasting period.

Phosphate preparations

These preparations (e.g Fleet, phosphor-prep) will exert a laxative effect either through oral route or through rectal passage and will make the intestine to retain large amounts of fluids and thereby distend itself allowing the faecal matter to pass. The preparations are very effective and patient compliance also seems to be better. But, the possibility of electrolyte disturbance prevents the use of phosphate preparations in the elderly and the ones who are suffering from kidney diseases.

Polyethylene glycol preparations

The substance comes with electrolyte supplements and would require the patient to take at least 3 – 4 litres of the dissolved substance within a stipulated time period. Due to its electrolyte content as well as water content, it does not cause the side effects associated with other electrolyte depleting and dehydrating laxatives. But the necessity to take large volumes of water mixed substance makes it difficult to be tolerated by many people.


These drugs will act locally and is given either as oral tablets or suppositories. The drug will stimulate bowel contractions or peristalsis and promotes water retention within the intestinal lumen. Thus, the increased bowel motions will do what is needed to prepare the bowels.

The surgeons will decide how a patient should be prepared for the bowel surgery or other interventions and these decisions will depend on the type of the surgery, location of the surgery, patient#s condition as well as the urgency to do the surgery.

Reference : Australian prescriber; last accessed on 17/12/2009