Yes, you can straighten natural hair with ceramic irons, but you may wanna get the hang of using a flat iron before spending hundreds of $$ on a ceramic. You can get great results just using a cheap ceramic-coated flat-iron that by Conair(paid about $20 for it at Wal-mart). My stylist uses the CHI brand flat-iron and its accompanying styling products. Here is my weekly hair wash/straighten routine:
1. Comb hair to remove tangles and separate into several ponytails (about 6 works for me).
2. Shampoo/rinse each ponytail individually, while finger-combing to prevent tangles.
3. Condition with a moisturizing conditioner and rinse.
4. Comb and apply a water-based moisturizer. I also like to use John Frieda's Frizz Ease Serum to seal the moisture and prevent frizziness.
5. Dry...I don't like blow drying b/c I get puffy hair and split ends, so I allow mine to dry in the small ponytails. If you choose this method, the roots of your hair will dry straighter from the tightness of the elastic bands/ponytail holder.
6. Apply a thermal protectant(Frizz Ease works for this!) and flat-iron each ponytail indivually. Part and comb out small sections less than 1 inch wide...Be sure to pull the hair taut-it allows you to get close to the roots without burning the scalp. IF YOU BURN YOUR SCALP, IT WILL HURT!! Otherwise, no, straightening your hair does not hurt...it's just a little time consuming. I developed my routine based on things I found at this website: www.blackhairmedia.com Just click on the forum link at the left and you'll find a wealth of info on both relaxed and natural hair care. By the way, my hair is relaxed, about mid-back length, but I have 2 inches of unrelaxed roots so I get better results with the wide plates, if your hair is shorter/thinner, you may like the 1/2 inch plates..Walmart sells a ceramic-coated one in this size for under $20 also...good luck! I would love to know how it worked for you :)