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.

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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.

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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.'