One of the curezone members sells it, http://www.ozonatedoilonline.com
that's where I found mine. YOu can invest in an ozonater and do your own, but I wanted to get it and get started on the clean up with the L-Cysteine right away.
He sells one that is more of a solid, that has been ozonated longer..or the "lighter" one that still meets the Hulda Clark recommendations. It comes out of Canada, and is shipped frozen.
I found the NOW product L-Cysteine, and 600mg of CoQ10 on iherbs.com- at 1/2 the price I found it in the Health food stores. That's also part of the Hulda Clark recommended clean up, 3000mg-4000mg occasionally of CoQ10, depending on your weight.
You can read about the Hulda Clark recommendations for tough worm cleanup on curezone-