Estrogenic Activity
The Memorial Sloan Kettering Cancer Center reports rooibos demonstrates estrogenic activity. If you have a hormone-sensitive cancer, like breast cancer, talk to your doctor about the appropriateness of consuming rooibos.
Interactions
Rooibos contains a number of antioxidants. While usually associated with positive actions, some concern exists over whether or not antioxidant-rich supplements interfere with the actions of chemotherapy drugs. Talk to your doctor before using rooibos tea if undergoing treatment for cancer. She might suggest timing your intake of rooibos based on your treatment schedule.