Elle Macpherson is getting candid about how she keeps healthy — and confessed to using an interesting product to keep her body in tip top shape!

When asked what the most surprising item in her purse was, the 51-year-old former model admitted she uses urine testers to monitor the pH levels in her body.

elle macpherson

Elle on vacation in July 2014.

“A pH balance urine tester kit to check that I’m in an alkaline state,” she revealed in a new interview. “I believe that most ailments come from having an acidic body.”

Related: Elle Macpherson, 50, Shows Off Her Amazing Bikini Body — See the Photo!

Elle further explained having an alkaline body helps the immune system defend against sickness and disease. To maintain a high pH level, “The Body” eats a diet high in leafy greens and exercises regularly.

elle macpherson

Elle at an event in January 2013.

As for her daily workout regimen? The mom-of-two says “variation is key.”

“I work out 45 minutes a day, six days a week, combining hiking, water skiing, swimming and running on the beach,” she told the ‘Evening Standard.’