An aphrodisiac is a substance alleged to increase sexual desire, sexual attraction, sexual pleasure, or sexual behavior. Substances range from a variety of plants, spices, foods, and synthetic chemicals. Natural aphrodisiacs like cannabis or cocaine are classified into plant-based and non-plant-based substances. There are non-naturally occurring aphrodisiacs like MDMA and methamphetamine. Aphrodisiacs can be classified by their type of effects (i.e., psychological or physiological). Aphrodisiacs that contain hallucinogenic properties like Bufotenin have psychological effects on a person that can increase sexual desire and sexual pleasure. Aphrodisiacs that contain smooth muscle relaxing properties like yohimbine have physiological effects on a person that can affect hormone levels and increase blood flow.

It is possible that the aphrodisiac effect of a substance is due to the placebo effect. Substances that impede on areas that aphrodisiacs aim to enhance are classified as anaphrodisiacs.

Both males and females can potentially benefit from the use of aphrodisiacs, but they are more focused on males as their properties tend to increase testosterone levels rather than estrogen levels. This is in part due to the historical context of aphrodisiacs, which focused solely on males. Only recent attention has been paid to understanding how aphrodisiacs can aid female sexual function. In addition, cultural influence in appropriate sexual behavior from males and females also play a part in the research gap.