The “no poo” online forum counsels people on regularity, but, the site assures through a small disclaimer, this regularity has nothing to do with digestion.

“No, we’re not constipated,” the blog’s tagline reads. “Yeah, we get that a lot.”

Daniel Kanaan, who hasn’t used shampoo in three years, shows off his Bird of Paradise hairstyle. Kanaan creates this do with nothing more than his hair’s natural oils. (Photo courtesy of Daniel Kanaan)

Instead, “poo” is short for “shampoo,” which the site’s 1,500 members have quit using. “New to no poo and this community, and so far, I love both!” gushed one acolyte in a typically effusive post. Such sentiments are echoed throughout many of the 13,000 comments generated since the forum launched in March 2006. And four years later, punching the words “no poo” into Google calls up more than 3 million hits.

The no-poo revolution harks back to a simpler way of life. A century ago, shampooing every day or even every week was virtually unheard of. A New York Times article from 1908 offered a tutorial on how to use shampoo, including a suggested timeline. “Several hair specialists recommend the shampooing of the hair as often as every two weeks,” the article reads, “but from a month to six weeks should be a better interval if the hair is in fairly good condition.”

The year that article appeared, Dr. John H. Breck Sr. developed one of the first liquid shampoos. He unleashed his “Breck girls” advertising campaign in the 1930s. Ever since, ads and the companies that make them have fed a consumer practice of more frequent washes.

The main appeal of ditching the poo seems to be a greener approach. Converts say the plastic containers and chemical components don’t jibe with an otherwise organic lifestyle. Shampoo strips out body-generated oils, and conditioner then compensates for the loss. The packaged process replicates nature, and no-poo believers argue that their bodies outperform any commercial brand.

Proselytizers say that nature’s oils and plain water — sometimes mixed with baking soda, apple cider vinegar, eggs, lemon juice, tea, honey, applesauce or beer — work better than any product. Going no-poo thickens and curls, they swear, and it gives luster and shine.

“It’s silly to wash all this stuff out and then put stuff back in,” says Daniel Kanaan, who has been poo-less for three years.

Kanaan, a 35-year-old American artist and Web developer living in France, says he ditched shampoo in part to make an anti-consumerist statement. But his choice was also environmental, and he can’t deny the stylistic benefits. His blog, noshampoo.org, displays photos to show how natural oils can hold a variety of coifs. The so-called Octopussy, for example, makes him look a bit like Medusa, while the Bird of Paradise resembles its floral namesake.

But the transition, Kanaan says, is not for the vain.

He endured six months to a year of grease until his locks acclimated. “It’s a bit like an addiction, actually,” says Kanaan, who has since inspired his 62-year-old mother as well as his wife and five children to scrap shampoo. “You think about it a lot.” Eventually, his head adjusted, and now he uses only water with a baking soda or lemon juice rinse two to three times a year.

Sarah Gilbert, 36, went no-poo about a year ago and suffered only three weeks of grease before her hair adapted. “It wasn’t like I was dripping with oil or anything,” says Gilbert, who lives in Portland, Ore., with her husband and three sons, who are now poo-free too. But, she admits, “I didn’t look awesome.” She started out supplementing hot-water rinses with baking soda and vinegar, but eventually she dropped the former from her beauty regimen. Her hair just started getting “really soft and sheeny,” Gilbert says. “I would brush my hair, and it looked great.”

Despite such success stories, Dr. Paul McAndrews doesn’t see a strong benefit to going no-poo. McAndrews, a dermatologist in Los Angeles who specializes in hair loss and transplants, says baking soda, one of the most popular poo alternatives, functions just like shampoo by stripping the natural oils from the hair.

He also debunked the claim that skipping on shampoo can cure thinning hair. “A lot of this is hocus-pocus,” he says.

Striking another blow to no-pooers is Sarah Janssen, an environmental-health expert with the Natural Resources Defense Council. She says that jettisoning shampoo alone would not significantly affect plastic or chemical pollution. Shampoos can be composed of chemicals like phthalates, surfactants and parabens, which have been linked to cancer, infertility and birth defects, she says. But those chemicals are not confined to shampoo. “They’re in other soaps that we use,” says Janssen. “It seems sort of a small part of a bigger problem.”

So maybe the trend won’t cure baldness or save the planet. But does poo-less hair look better? Rachel Phillips, a New York City-based hair stylist, says yes — for clients with dense, curly hair. But even they should use conditioner.

“Most people should use hair products if they want their hair to be healthy and/or look a certain way,” she says.