Yes. The Brazilian Blowout actually works best on chemically treated hair, and helps to improve the hairs condition by fortifying each strand with essential amino acids.
The Brazilian Blowout works great directly on top of a relaxer. Perform the relaxer first, Brazilian Blowout next, and then neutralize at the very end of both treatments.
The Brazilian Blowout is great to perform when someone is trying to move away from having relaxers or Japanese straighteners. It puts movement back into the hair, allowing the hair to look its best.