Apple cider vinegar has been claimed to help whiten teeth by attacking the plaque that turns them yellow.
The drink, produced from slowly fermented apples, has grown fashionable for its purported weight loss benefits thanks to a number of celebrity fans.
These include Jennifer Aniston, who recently revealed she takes it every morning along with vitamins.
What’s more, studies have found it can help diabetes sufferers manage their blood glucose levels, and it is said to help reduce risk of heart disease.
However, apple cider vinegar could also target yellow teeth – an unsightly health issue experienced by many.
A change in tooth colour can be inevitable as you age, since the outer enamel wears away and the yellowy dentin underneath becomes more visible.
But you can reduce this effect by using the vinegar in mouthwash.
Mixing two teaspoons with between 150ml and 200ml of water is said to whiten teeth.
Use it like a normal mouthwash by swishing the solution around for 30 seconds, before rinsing and brushing your teeth.
The claims are off the back of 2014 research which found apple cider vinegar had a bleaching effect on the teeth of cows.
Since human studies are needed to back up these findings, it should be used with caution.
Using too much for too long may damage the hardness of teeth.
For this reason apple cider vinegar for whitening is best used in small amounts for short amounts of time.
Another natural way to whiten teeth includes coconut oil pulling, since it is said to remove plaque and bacteria from the mouth.
However, other oils could be used too – a 2015 study found that oil pulling using sesame oil and sunflower oil reduced gingivitis caused by plaque.
It is thought that plaque build up that causes teeth to turn yellow could also have a whitening effect.