I use kojic acid products and find them very good. There are so many ingredients found in everyday skincare products that are somehow linked to cancer. But that doesn't mean they actually cause cancer in humans. And even if they do, its very rare and you usually have to be exposed to unnaturally high amounts. I bet if you googled all the ingredients in your daily moisturizer, you'd find at least one that is thought to cause cancer. I have done alot of online research on kojic acid and I have never found any real studies showing it causes cancer in humans.