Phosphate enemas, typically known under the brand name Fleet, are handy to have in the cabinet in case of constipation. Although the package says it’s a saline enema, it is more powerful than the saline we make at home with table salt and tap water. It uses a salt called sodium phosphate that draws water into the colon. It comes in its own convenient squeeze bottle with a soft nozzle that helps stimulate a bowel movement, or you can pour the solution in your homemade enema for occasional constipation or for a clean out.
They may be convenient, but phosphate enemas are not a recommended daily bowel program. First, these are low volume (120 ml) enemas–compared to those made at home with a higher volume of water/saline and soap–and cannot clean as far up in the colon. Second, the solution often comes right back out of a loose anus with no cone or balloon to hold it in, therefore it is ineffective. Third, they are not safe for long term daily use as they can cause a narrow and hyperactive colon and signs of colitis due to chronic irritation (source). Never use more than one Fleet enema per day. And those with kidney impairment should never use them.
A Pedia Lax enema is the exact same formula as the Fleet except half the volume. This size is recommended for children ages 5-11, and half of the bottle for children 2-4. However, you may ask your doctor whether a higher or lower dose would be appropriate for your child. Also, because the pediatric enema is the same formula as the adult enema, you can often save money by purchasing the adult size and simply using half the bottle.