A recent Groupon Deal of the Day offered a $35 colon hydrotherapy session at Ann Arbor’s Creative Lifeflow–half the regular price to “polish the pipes.” Center owner Nancy Gurney says it’s the third year she’s used the Chicago-based online coupon company to advertise the treatment, which uses a filtered water system to evacuate waste from the body.

Colon cleansing “changed my life,” says Gurney, forty-four. She describes a feeling of “clarity” so intense that after one session, “I felt like I could see behind me.” Gurney says she gets “lots of women in their forties and fifties” as clients and “for some reason I see a lot of U-M researchers and people in dentistry.” She thinks researchers may just be more open to new ideas. As for dentistry, she’s not sure. “Well, digestion does begin in the mouth,” she says.

Each of Gurney’s first Groupon offers brought in more than 250 people, but this time around it’s upwards of fifty, Gurney says, which makes her think she may have saturated the market. She says about 50 percent of the Groupon customers purchase a package from her for future sessions. Gurney says she’s used to all the poop jokes and laughs along with them. But she always lets her clients “take the lead,” because some people are “more serious than others.”