What is liquid paraffin?

Liquid paraffin or mineral oil is a transparent, colourless, odourless, or almost odourless, oily liquid composed of saturated hydrocarbons obtained from petroleum.1 Petroleum was used as a medicine at least 400 years before Christ.2 The earliest internal use of refined petroleum appears to date back to 1872, when Robert A. Chesebrough was granted a patent for the manufacture of “a new and useful product from petroleum”.۲ The use of liquid paraffin gained popularity, after Sir W. Arbuthnot Lane, Chief Surgeon of Guy’s Hospital in 1913, recommended its use as a treatment for intestinal stasis and chronic constipation.3

The popularity of liquid paraffin as a treatment for constipation and encopresis stems primarily from its tolerability and ease of titration. Although conversion of mineral oil to hydroxy fatty acids induces an osmotic effect,4 liquid paraffin appears to work primarily as a stool lubricant.5 Therefore, liquid paraffin is not associated with abdominal cramps, diarrhoea, flatulence, electrolyte disturbances, or the emergence of tolerance with long term usage, side effects commonly associated with osmotic or stimulant laxatives.6 These features make liquid paraffin particularly attractive for use in chronic constipation and encopresis of childhood, where large doses and prolonged administration commonly are necessary during the disimpaction and maintenance phases of treatment, respectively.6

However, although liquid paraffin is widely accepted and recommended as a fundamental component of regimens for the management of constipation in North America and Australia,6 7 it is little used in the United Kingdom.8 9 This trans-Atlantic dichotomy in liquid paraffin usage has been underscored by the American Academy of Pediatrics (AAP) endorsement of practice guidelines developed by the North American Society for Pediatric Gastroenterology and Nutrition (NASPGN) for the management of constipation in infants and children.6 NASPGN clearly identify liquid paraffin (mineral oil) as a medication of first choice in the management of paediatric constipation. Therefore, it is timely to reappraise the role of liquid paraffin in the management of childhood constipation and to explore the reasons underlying local distrust of this medication.