Bird poop for beauty?

That’s what goes into facials at a luxury spa where the traditional Japanese treatment using imported Asian nightingale excrement mixed with rice bran goes for $180 a pop.

About 100 women and men go into the Shizuka New York skin care salon, just off Manhattan’s Fifth Avenue, each month to get the treatment, which is promoted as a way to keep the face soft and smooth using an enzyme in the poop to gently exfoliate the skin.

Spa owner Shizuka Bernstein, a Tokyo native married to an American, has been offering what she calls the Geisha Facial for about five years.

“I try to bring Japanese beauty secrets to the United States,” says Bernstein, who learned the treatment from her mother.

The Geisha Facial poop treatment, while relatively rare in the United States, is no secret in Japan, where it was first used in the 1600s by actors and geishas.

“That’s why Japanese grandmothers have beautiful complexions,” says Duke Klauck, owner of the Ten Thousand Waves health spa in Santa Fe, N.M., which offers a Nightingale Facial for $129.

On a recent afternoon in Manhattan, Mari Miyoshi arrived at the sixth-floor Shizuka New York spa to try the treatment for the first time.

“I’m a stressed-out New Yorker,” the 35-year-old occupational therapist announced as she reclined on a table, relaxing amid aromas of camellia, lavender and rose.

The treatment begins with steam to open the pores and soften the skin. Cream is applied. And then comes what Bernstein calls “the nightingale part.”

She pours the cream-colored poop, dried and finely ground, into a bowl, mixing it with the rice bran using a small spatula. She applies the potion to Miyoshi’s face with a brush, rubbing it in with her hands.

Does it smell?

“Yes, but like toasted rice,” Miyoshi says.

After about five minutes, it comes off with a foaming cleanser and Miyoshi’s face is draped in a warm, wet towel bathed in lavender and geranium essences. Finally, the grand finale — a green-tea collagen mask.

“Sooooo nice,” Bernstein says softly, looking at Miyoshi’s radiant face.

Dr. Michele Green, a Manhattan cosmetic dermatologist, says that while the nightingale facial “definitely has some rejuvenating effect, I don’t think it’s any different than, say, an apricot scrub or a mask that you could buy in a local pharmacy.”

A common misconception is that any old bird poop, even from pigeons, is used. Bernstein says only droppings from birds of the nightingale species are used because they live on seeds, producing the natural enzyme that is the active ingredient.

“We don’t do Central Park facials,” she says, “because those birds eat garbage.”