Phosphate-buffered saline (PBS) is a buffer solution used in biological research. It is a water-based salt solution containing sodium phosphate, sodium chloride and, in some formulations, it contains potassium chloride and potassium phosphate. The osmolality and ion concentrations of the solutions match those of the human body (isotonic) and are non-toxic to most cells.

Phosphate-buffered saline has been used:

• as a reagent in the isolation of human endometrial stem cell/stromal cells (hEnSCs) from the endometrium or menstrual blood
• has also been used to wash cells during immunofluorescence staining
• as a solvent for the glucose administered orally in the Glucose Tolerance Tests (GTTs)