Use the search bar to find a specific medication or choose the first letter in the sidebar on the right.

Polyethylene Glycol

Generic Name

Polyethylene Glycol (PEG)


Trade Name



What is Polyethylene Glycol?

PEG is a solution that stays within the intestinal tract. It is not absorbed. It acts to keep fluid in the gut, thereby flushing and cleansing it. The solution is primarily sodium sulfate which acts to keep the sodium from being absorbed. Therefore, people on sodium restricted diets can use this product.


What is it used for?

PEG is used to cleanse the lower GI tract prior to colonoscopy (an endoscopic exam of the colon) and barium enema. It has also been used in modified form for severe, hard to manage constipation and, in children, when excessive iron medicine overdose has occurred.


How do I take it?

Follow your physician’s instructions carefully. Do not add flavorings or other ingredients to the solution. Do not eat solid food for 3 to 4 hours prior to drinking the solution. Drink 8 ounces every 10 minutes until all 4 liters (1 gallon) are consumed. Drinking each portion rapidly is better than drinking small amounts continuously. The first bowel movement should occur in approximately 1 hour. Continue drinking until watery stool is clear and free of solid matter.

To prepare: Add tap water to make 4 liters (1 gallon). Refrigerate to improve taste. Use within 48 hours.


Are there interactions with other drugs?

An interaction generally means that one drug may increase or decrease the effect of another drug. Also, the more medications a person takes, the more likely there will be a drug interaction. Oral medication taken within 1 hour of this product may be flushed through the GI tract and not absorbed. Check with your physician or nurse.


Are there interactions with food or beverages?

The combined use of acetaminophen and alcohol should be avoided to prevent the possibility of severe liver damage.


Are there interactions with other drugs?

An interaction generally means that one drug may increase or decrease the effect of another drug. Also, the more medications a person takes, the more likely there will be a drug interaction.

Interactions with this drug may occur with the following:

  • cholestyramine (Questran)
  • isoniazid (Rifater)
  • phenytoin (Dilantin)
  • blood thinners (Coumadin)
  • zidovudine (Retrovir)
  • birth control pills
  • non-steroidal anti-inflammatory drugs-commonly called NSAIDs


Is there a problem if I have another disorder or disease?

At times, a drug may have a different or enhanced effect when other diseases are present. At other times, the drug may worsen or effect another disease. Patients with severe ulcerative colitis or congestive heart failure should discuss its use with their physician. Generally, this product can be used with almost any other medical condition.

What about allergies?

People who have known allergies or asthma may be at an increased risk for a reaction from any new medication. The physician should always know a patient’s allergy history. Signs of an allergic reaction are itching, runny nose and skin rash. Of course, a person should not take Polyethylene Glycol if there has been a previous reaction to this or a similar drug.


What if I’m pregnant, considering pregnancy or breast-feeding?

Most females now know that, if possible, no drug, including alcohol, should be taken during pregnancy or lactation. The potential danger, of course, is an injury to the baby. However, some drugs are much safer than others in this regard. So, the FDA has a grading system for each drug which reflects what is known medically. It ranks drugs from A, where medical studies show no evidence for danger to the fetus or mother, to B, C, D and X, where the medical evidence indicates that the risk to the fetus outweighs any benefit to the mother. Polyethylene Glycol is ranked C. Always consult your physician before taking any drug during or when planning pregnancy.


How about side effects?

Adverse reactions can occur with any drug, even over-the-counter medications. Minor reactions may go away on their own but if they persist, contact the physician. For major reactions, the patient should contact the physician immediately.

For Polyethylene Glycol, the following are the observed side effects:


  • nausea
  • abdominal fullness
  • bloating
  • cramps
  • vomiting
  • chills
  • anal irritation


  • severe bloating
  • distention
  • abdominal pain


A physician’s comment…

PEG is an excellent method of cleansing the colon. The cleaner the colon, the better the endoscopic exam. Remember, the product must be taken as instructed. If you have trouble swallowing it or keeping it down, contact your physician or hospital immediately for instructions.