Depending on the formula, it can contain formaldehyde, a known carcinogen, and a substance that the Food and Drug Administration doesn't regulate. It can irritate the eyes and lungs when it undergoes the heating process necessary for the treatment to work. Both stylists and clients have complained of nausea, sore throat and asthma-like symptoms when either administering or undergoing the treatment, not to mention the skin irritation involved. If you're interested in the Brazilian, then ask your stylist whether she's certified to do it and if her preferred formula has formaldehyde. Celebrities swear by salon owner Andy LeCompte's version, the Brazilian Blowout. Lindsay Lohan, Nicole Richie and Ashley Tisdale have sung its praises, and LeCompte tells Glamour magazine that his concoction has no formaldehyde. The bottom line is that the results make the treatment tempting to try - just do your homework first.