You might have seen Jessica Alba kill a bad guy with a stiletto heel in the gory action flick Machete. You might also have spotted her on the cover of Maxim (twice). But fewer people probably caught her on C-SPAN lecturing Congress about the urgency of passing laws to regulate the chemicals in the products we buy. A staunch environmental advocate, the 31-year-old star recently launched the Honest Company, which makes nontoxic, ecofriendly baby gear.

Q: WHY DID YOU GO TO D.C. TO LOBBY FOR THE SAFE CHEMICALS ACT LAST YEAR?

A: Basically, it's legislation that hasn't been reformed in more than 30 years. It's about regulating chemicals in everyday products. There are more than 80,000 chemicals in the U.S. marketplace right now—only 5 have been banned. In Europe, 1,100 are banned because they're not safe for humans. When they're creating and selling new chemicals, companies aren't thinking about how they affect people's health—it's about their bottom line.

Q: YOU HAD ASTHMA AS A KID, RIGHT? DOES THAT MAKE YOU WORRY MORE ABOUT AIR POLLUTION?

A: I grew up with asthma and allergies, among other health issues. That forced me from a very early age to look at my environment in a different way. I don't take things at face value. I don't automatically trust the conglomerates. I question processes, I question ingredients, I look for a better way. I always try to find a more natural and holistic approach before just slapping on a Band-Aid. Better to prevent something from happening in the first place.

Q: WE ASSUME THAT YOU'RE THE ONLY WOMAN WHO'S TOPPED MAXIM'S "HOT 100" LIST AND ALSO TESTIFIED BEFORE CONGRESS ABOUT ENVIRONMENTAL LEGISLATION. HOW DO YOU WALK THAT BALANCE?

A: [Laughs] I don't know. I don't even really think about it in those terms. The marketing I've done to promote TV and film has been wonderful because it's given me a platform to be able to speak about things that are important to me.