No food has ever been shown to be an aphrodisiac

The candidates have been tested, and the pattern is consistent: any effect disappears when the participants do not know what they are eating. Oysters are high in zinc, which matters for testosterone production if you are deficient — which, on an ordinary diet, you are not. Chocolate contains phenylethylamine, which is broken down before it reaches the brain.

Expectation, however, works. Believing something is an aphrodisiac reliably produces reported arousal, which is a real effect with a boring cause. The one substance with genuine pharmacological action, Spanish fly, works by irritating the urinary tract and is toxic in small doses.