It is used as a laboratory reagent and pH indicator. Phenolphthalein is a common indicator to use in neutralization titrations. Phenolphthalein exerts laxative effects by stimulating the intestinal mucosa and constricting smooth muscles. It is used medicinally as a cathartic.

This Thermo Scientific Chemicals brand product was originally part of the Alfa Aesar product portfolio. Some documentation and label information may refer to the legacy brand. The original Alfa Aesar product / item code or SKU reference has not changed as a part of the brand transition to Thermo Scientific Chemicals.