Have you had a shrub? No, not that kind of shrub.

Shrubs, or drinking vinegars, are appearing on more and more cocktail menus across New York City. A shiso shrub appears in the El Ninja cocktail at Cosme, the new and much hyped Mexican restaurant from Mexico City chef Enrique Olvera. When Russ & Daughters Cafe opened earlier this year, shrubs were prominently featured on the menu. Pok Pok NY, Andy Ricker's Thai restaurant on Columbia Street in Brooklyn serves Som drinking vinegars in cocktails and straight up. (They are bottled and sold, too.)

For answers, we turned to Michael Dietsch, author of the new book "Shrubs: An Old-Fashioned Drink for Modern Times."

A shrub, we learned from Dietsch's book, is actually an ancient beverage. The name is derived from the Arabic word sharab, which means to drink. Made of fruit, vinegar and sugar, the taste is complex and gives a mixed drink a lot of character.

"The American palate for cocktails is getting more sophisticated, slowly, as the craft cocktail has left the coast and moved into the center of the country," said Dietsch in a phone interview.

The "giant 12-ounce bucket of appletini" is on the way out he said, and more complex drinks are on the way in. We think he's right.

Here are some NYC restaurants offering mixing shrubs into cocktails:

Cosme: The El Ninja cocktails is made with Union mezcal, Beefeater gin, Cocchi Americano vermouth, shiso shrub (shiso is a tangy Asian herb, also called perilla), ginger, lime and dehydrated pineapple. $14. 35 E. 21st St., cosmenyc.com

Decoy: The sister restaurant to RedFarm that serves Peking Duck with all the fixin's also makes cocktails with shrubs. The Ain't That a Peach cocktail is made with Tin Cup whiskey, peach shrub, Meletti, Averna, lemon and peach bitters. $14. 529 1/2 Hudson St., decoynyc.com

Russ & Daughters Cafe: Shrubs and other "old-school" beverages like egg creams and sodas made with seltzer and syrup are available at the new Cafe and the Russ & Daughters appetizing store around the corner has sold a beet and lemon shrub since 2010. Pro tip: add booze to a shrub. The bartenders will not only do this for you, they will suggest pairings. We loved the cherry shrub with gin. 127 Orchard St., russanddaughterscafe.com

Colonia Verde: This artisinal and Spanish-influenced steak house in Fort Greene opened last winter and features a steller shrub cocktail called La Fresa, with tequila, mezcal, lime juice and a strawberry & jalapeno shrub. $11. 219 DeKalb Ave., Fort Greene, coloniaverdenyc.com

Dietsch devotes a large part of his book to the history of the shrub, from its early days - 1737 is the year of one of the earliest known shrub recipes - to its history as a medicinal beverage.

You can also make shrubs yourself.

"You can easily make them at home. It becomes another way to use fresh produce," he said. "That's the other part of the rise of interest with consumers. There's an uptick in greenmarket shoppers, and if you've got peaches that sat out too long, you can shrub those up."

For those who consider the idea of drinking vinegar with distaste, Dietsch says just try it on a hot summer day.

"I've seen people who are skeptical and they take the first sip and they're suddenly a convert," he said.

Recipe for Cataloupe-Mint Shrub, from "Shrubs" by Michael Dietsch

1 1/2 pounds cataloupe, cut into chunks

3/4 cup raw cane sugar

1/2 ounce mint leaves, bruised

3/4 cup white wine vinegar

1. Add cantaloupe and sugar to a bowl, stir, cover and leave to macerate on the counter for 2 hours.

2. Add mint leaves to vinegar in a nonreactive container

3. After cantaloupe has macerated, drain off the liquid and set aside. Discard the solids. Add liquid to mint and vinegar. Place in refrigerator for up to 1 week.

4. Taste until you're happy with the level of mint flavr. At that point, strain out the mint and discard the leaves.