In the pharmaceutical industry it can be used as an intermediate of cefadroxil, vasodilator cyclomandelate, eye drops hydroxybenzazole, pemoline, etc.
It can also be used as a preservative.
Mandelic acid is used Chemicalbook as a preservative (urine).
It is also used as a short-term exposure biomarker in the urine of styrene exposed workers. Special reagent for zirconium, determination of copper, organic synthesis, fungicide.