The practice of washing hair has been around since at least 2000 B.C., when the Egyptians made what may have been the first shampoo from citrus juice and used animal fats and plant oils to restore their locks' luster. That's probably also around the time that someone first uttered the phrase, "I just washed my hair and I can't do a thing with it." Over the centuries, people discontented with wet shampooing's tendency to make the hair dry and frizzy have experimented with all sorts of après-wash treatments. In 12th century Europe, for example, women favored a conditioner made by boiling dead lizards in olive oil [source: Scott]. They've also complained about the inconvenience, effort and sometimes unflattering results of wet shampooing and drying.
"The wet shampoo is exhausting in itself," a New York Times writer lamented in a 1909 article. The newspaper reported that turn-of-the-20th century Paris stylists had devised a bizarre alternative: They treated clients' hair with a mixture of gasoline and ether fumes, applied next to a window with an electric fan running to reduce the chance of an explosion [source: NYT].
Eventually, hair care mavens came up with a less dangerous solution. Instead of using detergent and water to strip away oil from the hair, they tried absorbing it -- basically, the same way that talcum powder sops up moisture from your skin. This wasn't an entirely new idea: People in Asia used sprinkled clay in their hair for centuries, and elegant ladies in 18th century France had powdered their hair to color it [source: Berg]. The 1918 edition of the American Journal of Pharmacy described one such dry shampoo preparation containing rice flour, with the instructions that it should be "sprinkled among the hair and brushed off with a clean brush, prolonging the draw of the brush to the end of the hairs" [source: American Journal].
Since then, various dry shampoo products on the market have utilized starches, clays, vegetable powders and various chemicals with oil removing properties [source: Bouillon]. Some can be sprinkled on the hair, while others come in the form of aerosol sprays. Dry shampoos were marketed enthusiastically in the 1970s, back when consumers were crazy about time-saving innovations. But their popularity waned after that [source: McCoy]. Recently, though, they've undergone a resurgence, which we'll discuss in the next section.