It's commonly said that the Aztecs considered chocolate to be an aphrodisiac, and the claim has been repeated by many-a pseudo-scientist. However, studies have shown that chocolate only actually has trace amounts of the chemical compounds tryptophan and phenylethylamine, the brain chemicals which enhance sexual desire and simulate falling in love, respectively. Not only that, but there's also a debate about whether there's even such a thing as an aphrodisiac.