Rose bengal

Rose bengal sodium is a stain, commonly used in eye drops to stain damaged conjunctival and corneal cells and thereby identify damage to the eye.

The stain is also used in the preparation of Foraminifera for microscopic analysis, allowing the distinction between forms that were alive or dead at the time of collection.

A form of Rose Bengal is also being studied as a treatment for certain cancers. The company, Provectus Pharmacuticals, renamed the drug PV-10 and is currently undergoing clinical trials for melanoma.

Chemical Applications
Rose Bengal is also used in synthetic chemistry to generate singlet oxygen from triplet oxygen. The singlet oxygen can then undergo a variety of useful reactions, particularly [2 + 2] cycloadditions with alkenes and similar systems.