What would be the benefit of chemotherapy after cancer rather than mistletoe extract?

Chemotherapy: Many of our modern chemotherapies originated with plants or other natural compounds. One example is Paclitaxel (taxol) came from the pacific yew tree. Chemotherapies go through rigorous trials to test safety and efficacy. Although there may be potential benefit, most over the counter herbs or herbal remedies have never been tested for safety or efficacy.