BMJ Group Medical Reference
Glycerol is also sometimes called glycerin. It helps you to go to the toilet by stimulating your bowels. 
Glycerol comes as a suppository, which is a tablet that you insert into your back passage.
We couldn't find any studies looking at how well glycerol suppositories clear constipation. Nor could we find any evidence that they can be harmful.
©2009-2014 WebMD UK Limited and Boots UK Limited. All rights reserved.
BootsWebMD does not provide medical advice, diagnosis or treatment. See additional information.
To provide even greater transparency and choice, we are working on a number of other cookie-related enhancements. More information