Bacteriostatic Water vs Sterile Water vs Saline

Bacteriostatic water, sterile water and saline are three different liquids. The main differences are whether there is a preservative in them and whether there is salt.

Side by side

	Bacteriostatic water	Sterile water	Saline (0.9% sodium chloride)
What is in it	Sterile water and 0.9% benzyl alcohol	Sterile water only	Sterile water and 0.9% sodium chloride (salt)
Preservative	Yes, benzyl alcohol	No	No, unless it says bacteriostatic
Once opened	Made to be opened more than once	Normally used once, then thrown away	Normally used once, then thrown away
Salt content	None	None	Yes

Bacteriostatic water

This is sterile water with 0.9% benzyl alcohol added. The benzyl alcohol is a preservative. It stops bacteria growing when a vial is opened more than once.

Sterile water

This is water that has been made sterile and has nothing added. Because there is no preservative, an opened vial is normally used once. Sterile water for injection is a prescription-only medicine in the UK.

Saline

Saline is sterile water with 0.9% sodium chloride added, which is the same salt level as body fluids. Saline for wound washing and for nasal rinses is sold widely. Saline for injection is a prescription-only medicine in the UK. There is also bacteriostatic saline, which has both the salt and the benzyl alcohol.

Which one do we sell?

We only sell bacteriostatic water in 10ml vials, for laboratory use only. Boxes start at 3 vials. See buy bacteriostatic water in the UK.