Aromatherapy is the pure, clear, aromatic liquid extracted from aromatic plants and medicinal plants, which is called “essential oil” in English. The Chinese translation is “essential oil”, “fragrance oil”, etc. It is used as a complementary therapy to treat physical diseases and to achieve balance and health for body, mind and soul. The history of the use of essential oils is as old as the history of mankind, and its origins are untraceable. The earliest documented use of plants in medicine is the “Materia Medica” written by the Chinese 2,000 years ago. The earliest widespread use of essential oils was in ancient Egypt, where they were used to worship the gods, treat illnesses, and improve beauty. During World War II, essential oils became a natural antiseptic and were used to disinfect medical instruments. For cancer patients, the fear of cancer comes from the difficulty of curing it and the many discomforts that come with treatment, such as general weakness, pain, nausea, vomiting, and even the anxiety and depression that comes with the disease process. Many cancer patients often experience a reduced appetite, which can be improved by using sweet orange essential oil. Bad odor in the mouth and wounds can be improved with tea tree or peppermint puree. Body edema can use grapefruit, lemon, happy sage, juniper and other essential oils, together with lymph node massage, will have a good effect. Most cancer patients can not tolerate the pain, then use happy sage, sweet marjoram, Roman chamomile, German chamomile, lavender and other essential oils. Let cancer patients suffer from anxiety, depression and other depressed mood problems, use neroli, happy sage, bergamot, frankincense, sandalwood, grapefruit, sweet orange, rosemary, sweet marjoram and other essential oils to improve the mind and mood fatigue, so that cancer patients open their hearts and relax the nervous emotions. In addition, cancer patients because of the decline in immunity, often lead to the wound is not easy to recover, you can consider using lavender, tea tree oil, German chamomile and other essential oils applied to the wound, will promote the recovery of the wound tissue. And if the nausea and vomiting caused by chemotherapy, you can use lemon, sweet orange, peppermint, ginger and other essential oils, with aromatherapy way for patients to inhale, can improve the patient’s nausea and vomiting situation. Due to disease or medication caused by constipation or bloating, you can give neroli, sweet orange, frankincense, grapefruit, bergamot, lemon and other essential oils to massage the abdomen. Aromatherapy is a mild complementary therapy, can not be used to destroy cancer cells, but the seemingly simple essential oils if you can properly use in cancer patients, can certainly alleviate the discomfort of the patient’s body and increase the spiritual relief, to promote the smooth process of disease treatment, improve the quality of life of patients, and then can actively face cancer treatment, for cancer patients, is a good helper.