For several months, Yee, a young Chinese-American medical anthropologist has been working with elderly Chinese in an urban area. Mrs. Lee has asked him to drive her to a doctor's appointment at a nearby clinic and act as interpreter for her. After the doctor's visit, Mrs. Lee asks Yee to have tea with her in her home. Yee notices that the interior of the tea cups are stained yellow and asks her about this. She explains that she makes ginseng tea for herself daily to help preserve her health. Yee asks Mrs. Lee why she did not tell the doctor about this medicine? What could be a possible reason?