Coriolus versicolor, also known as turkey tail mushroom, has been used in traditional Chinese medicine for thousands of years. Recent scientific research shows it may help fight breast cancer through multiple mechanisms: killing cancer cells directly through programmed cell death pathways, breaking down the estrogen that fuels some breast cancers, preventing cancer spread, and boosting the immune system. While early studies are promising and one clinical trial showed good safety and immune benefits, larger studies are needed before this mushroom can be recommended as an official cancer treatment.