Glycerin (Glycerol) Suppositories Bp 4g Adult helps to relieve occasional constipation by helping to make bowel movements easier and comfortable. Glycerin (Glycerol) Suppositories Bp 4g Adult helps to stimulate bowel movements to move the stools along and makes passing them out of the body much easier. The active ingredients, glycerin acts as a lubricant and mild irritant to help stimulate the muscles of the intestine, causing it to contract for easier bowel movements.