The “Preface to this Classic” states, “Do not use the opposite of the opposite.” However, the consequences are not the same for the opposite and the opposite. The opposite of the opposite can make some aspects of the drug less effective, but it is a relationship that can be used, not an absolute contraindication. The opposite is more harmful than the opposite, and may endanger the patient’s health and even life. Therefore, the application of opposite drugs is prohibited in principle. At present, there are eighteen contraindications and nineteen contraindications that are commonly accepted in medicine. Eighteen contraindications: Glycyrrhiza glabra against Gansui, Euphorbia grandis, Morinda citrifolia, Ocimum sanctum against Phellodendron, Gourd basket, Semen, Bupleurum, Bupleurum; Quercus rehmanniae against Ginseng, Salvia, Salvia, Radix et Rhizoma, Radix et Rhizoma bitter, Radix et Rhizoma paeoniae. Nineteen fears: sulphur yellow fears park nitrate, mercury fears arsenic, wolfsbane fears mithril, croton fears petunia, clove fears tulip, Chuanwu, Cao Wu fears rhinoceros horn, tooth nit fears trigonella, Guan Gui fears stone resin, ginseng fears five lingzhi. When Han Baosheng revised the Shu Materia Medica in the Fifth Dynasty, he first counted the number of the seven emotions, mentioning that “there are sixty kinds of the phase, and eighteen kinds of the opposite”, and the name of the so-called “eighteen anti” is derived from this. The name of the so-called “eighteen opposite” originated from this. However, since the Song Dynasty, there has been confusion in the use of the names of fear, evil and opposite in some medical writings, which is contrary to the original meaning of “phase fear” in the book. It is in this context that the “nineteen fears”, which is a contraindication to the use of medicines, were introduced. For the eighteen anti, nineteen fear as a combination of taboo, although the majority of medical scientists over the ages to comply with the letter, but there are also different views, some people believe that eighteen anti, nineteen fear is not an absolute taboo; some medical scientists also believe that the opposite of the drug used together, can be the opposite of each other to produce a stronger effect. If used properly, it can heal the disease and chronic illness. Modern pharmacological experimental research on the eighteen anti and nineteen awe has made a lot of achievements. However, because of the problems involved in the eighteen anti, nineteen awe, there are differences in the experimental conditions and methods around the world, so that the experimental results vary greatly. Most of the simple toxicity tests yielded negative results or conflicting results. The results of the early studies tended to be totally negative; in recent years, the observation has been gradually deepened, and the voice of “not to be easily rejected” has become higher. In addition, there are experimental evidence that the size of the toxic side effects of the eighteen anti and nineteen dreadful drugs on human body is related to the absolute dose of the drugs and the relative dose between each other. In general, because the experimental research on the eighteen anti and nineteen fears is still at an early stage, it is still too early to decide the trade-offs, and further in-depth research is needed. Therefore, if there is no sufficient basis and experience in the application of the eighteen anti, nineteen fear of the drug pairs, generally should not be used. The main discussion is on contraindications to pregnancy drugs. Pregnancy contraindications refer to the drugs that are contraindicated during pregnancy, except for interruption of pregnancy and induction of labor. In the Eastern Han Dynasty, the Shen Nong Ben Cao Jing contains six kinds of drugs with abortifacient effects, and in the Liang Dynasty, the “Collected Notes on the Materia Medica – Preface – General Drugs for All Diseases” contains 41 kinds of abortifacient drugs. From the historical point of view, in ancient times, abortion was against our traditional moral concept. Therefore, the abortifacients were mainly recognized and treated from the perspective of contraindications to pregnancy, rather than seeking effective abortifacients. Among the many contraindicated medicines for pregnancy, the degree of harm to pregnancy varies from one medicine to another, so they should be treated differently in clinical practice. In ancient times, contraindications to pregnancy were mainly prohibited and contraindicated, but rarely used with caution. In recent times, according to clinical practice, pregnancy contraindications are divided into two categories: prohibited and caution. The prohibited drugs are mostly highly toxic, or the effect of harsh drugs, and strong abortifacient effect of drugs. The cautionary medicine is mainly to activate the blood to dispel blood stasis drugs, qi drugs, attacking drugs, warming drugs in the part of the drug. Forbidden drugs: mercury, arsenic, stellaria, light powder, spotted cucumber, strychnine, toadflax, Chuanwu, Cao Wu, quinoa, bile alum, guati, croton, Gansui, halberd, coriander, petunia, Shangluo, musk, dry lacquer, leech, gadfly, trigonella, curcuma, etc. Cautionary medicines: hyssop, chuanxiong, safflower, peach kernel, turmeric, peony bark, hedgehog, hedgehog, rhubarb, senna, aloe, mangosteen, epilobium, cinnamon, etc. Among the many contraindicated drugs for pregnancy, there are various reasons for pregnancy contraindication, among which, the ability to cause abortion is the main reason for early pregnancy contraindication. As the knowledge of contraindicated drugs for pregnancy gradually deepens, the understanding of the reasons for pregnancy contraindication also gradually deepens. In summary, the main reasons include: (1) unfavorable to the mother, (2) unfavorable to the fetus, (3) unfavorable to the labor process, and (4) unfavorable to the child. Today, whether from the perspective of drug safety or from the perspective of eugenics to understand these points, should be given great attention. In general, for pregnancy contraindications, if there is no special need, should be avoided as far as possible to avoid accidents. If a pregnant woman has to use it, she should pay attention to the accurate identification of the evidence, master the dosage and course of treatment, and through the appropriate preparation and combination to minimize the harm of drugs to pregnancy, so as to achieve effective and safe use of drugs. Third, when taking drugs diet taboos medication diet taboos refers to taking drugs during the contraindications to certain foods, also known as food taboos, which is commonly known as taboo. Generally speaking, you should avoid eating cold, hot, greasy, fishy, irritating food, in addition, according to the different conditions, dietary contraindications are also different. For example, hot disease should avoid eating spicy, greasy, fried food; cold disease should avoid eating cold, chest paralysis patients should avoid eating fat, fat, animal offal and tobacco, alcohol; liver Yang, dizziness, irritability, etc. should avoid eating pepper, chili, garlic, white wine and other hot and spicy products to help Yang, spleen and stomach weakness should avoid eating fried sticky, cold and hard, indigestible food, sores, skin disease patients, should avoid eating fish, shrimp, crab Patients with sores and skin diseases should refrain from eating fish, shrimp, crab and other fishy and spicy foods.