Herbs and botanicals, e.g., St John’s wort, garlic oil, Panax ginseng, and Ginkgo biloba, as well as grapefruit juice alterate CYP3A4 enzyme activity and when taken with certain medication (e.g., CLL therapy) may lead to herb-drug interactions. Here, CYP3A4 is linked to B-cell chronic lymphocytic leukemia.