Fresh watermelon has a similar effect to taking Viagra, according to scientists.
But men would have to eat at least six slices to have the same effect as one Viagra tablet - and it's not as 'organ-specific'.
Watermelons contain an ingredient called citrulline that can trigger production of a compound that helps relax the body's blood vessels, similar to what happens when a man takes Viagra.
Found in the flesh and rind of watermelons, citrulline reacts with the body's enzymes when consumed in large quantities and is changed into arginine, an amino acid that benefits the heart and the circulatory and immune systems.
"Arginine boosts nitric oxide, which relaxes blood vessels, the same basic effect that Viagra has, to treat erectile dysfunction and maybe even prevent it," said Bhimu Patil, director of Texas A&M University's Fruit and Vegetable Improvement Centre.
"Watermelon may not be as organ-specific as Viagra, but it's a great way to relax blood vessels without any drug side effects."