Glycerol is also known was glycerin.
Glycerol is a clear liquid with a viscous consistency.
("Viscous" means very thick e.g. flows more like treacle
than like water - but the term "viscous" conveys no information
about colour or transparency).
Glycerol can be produced by hydrolysis of fats and
mixed oils, e.g. as a by-product in the manufacture of soap.
What does it do:
Glycerol has various uses, such as an emollient
in some skin products, as a sweetening agent in some pharmaceutical
products, and as a laxative
(e.g. in the form of suppositories). The use of glycerol for
its laxative effects is relevant to the digestive system.