Talcum powder, the main ingredient for Shower to Shower, has been linked to two types of cancers: mesothelioma and ovarian cancer. Mesothelioma occurs when asbestos-contaminated talcum powder is inhaled by users. While the mechanisms that cause ovarian cancer are still being researched, it’s believe that talcum powder makes its way through the vagina and into the ovaries. Here, it somehow irritates the tissue and triggers the development of cancer in cells there. The World Health Organization asserts that there is no acceptable amount of exposure to asbestos.