1, ClinicalTrial, refers to any systematic study of drugs in humans (patients or healthy volunteers) to confirm or reveal the effects of the test drug, adverse effects and/or absorption, distribution, metabolism and excretion of the test drug, with the aim of determining the efficacy and safety of the test drug. Clinical trials are generally divided into phase I, II, III, IV clinical trials and EAP clinical trials.2. According to the definition of clinical trials in the “Quality Management Standards for Drug Clinical Trials” issued by the State Food and Drug Administration, a clinical trial is any systematic study of a drug in humans (patients or healthy volunteers) to confirm or reveal the action, adverse effects and/or test drug Drug absorption, distribution, metabolism and excretion, the purpose is to determine the efficacy and safety of the test drug. In foreign countries, the participants of clinical trials are called volunteers, and in China, they are generally called “subjects”, and there are healthy people and patients among the volunteers, depending on what kind of trials they are participating in. We usually contact the most trials, or by the patient to participate in the purpose of examining the new drug has no efficacy, there are no side effects of the test, another more straightforward way of saying, is that in a new drug before the official launch, the doctor let the patient take (use) the new drug, of course, this must get the patient’s consent, after a certain course of treatment, to see the efficacy of the drug and side effects. The most important point of the clinical trial is that it must meet our ethical requirements, that is to say, the participant in the trial is a human being, his or her personality must be respected, and participation in the trial must be in the interests of the participant, under this premise, the trial can be done. Moreover, during the trial, the participant may not continue the trial without any reason, and his (or her) choice is not subject to interference by everyone, including the physician. In short, well-designed and operated clinical trials are the fastest and safest way to improve human health and find new therapeutic drugs and methods.3. The significance of clinical trials for new drug research and drug marketing mainly includes the following aspects: (1) to provide the reporting information required by regulations for the review and registration of new drugs The information of clinical studies is the main basis for drug regulatory authorities to review drug registration applications and issue marketing licenses or It is also the main basis for the approval of new drug standards, new drug labels, instructions and advertising materials. In China, the following information is required to be submitted for new drug registration: literature and abstracts of relevant clinical trials at home and abroad; clinical trial plan and study protocol; clinical investigator’s handbook; sample informed consent form, ethics committee approval; clinical trial report. (2) Provide a basis for enterprises to make decisions on new drugs and market development Through the information obtained during and after clinical trials, enterprises can predict the possibility of obtaining approval from drug regulatory authorities for drugs under development and the risks and benefits of drugs after they are marketed, so as to decide on strategies for further research and market development, and timely adjust the direction of research based on the findings in clinical trials to discover more valuable For example, Sildenafil Citrate, or Viagra, a drug for sexual dysfunction, which has brought huge economic benefits to Pfizer Inc. in the United States, is an example of a drug that has achieved great success by adjusting its main focus to the side effects found in clinical trials in a timely manner. In addition, after a new drug is approved for marketing, the results of clinical trials can guide companies and regulatory authorities in determining the indications for the drug, the use of advertising slogans, contraindications, and the content of labels and instructions in promotions. After all, the sample size of clinical trials of pre-marketing drugs is limited, and the monitoring trials of post-marketing adverse drug reactions (Phase IV clinical trials) can be more helpful for companies to adjust their marketing strategies in a timely manner and decide whether to increase market development efforts or withdraw the new drug from the market or restrict the use of the new drug in a timely manner. The same is true for Pfizer’s antibiotic product, travafloxacin, which was found to cause serious liver damage during further post-marketing surveillance and was restricted from use. (3) Provide a basis for doctors and patients to use new drugs correctly Before doctors start to accept and use a new drug, they need to know information about the drug, such as indications, efficacy, dose, duration of treatment, adverse reactions, drug interactions, etc., which mainly comes from clinical trials before the new drug is marketed and is summarized in the new drug specification, and with the development of phase IV clinical trials after the new drug is marketed and the further expansion of clinical applications, the information is gradually supplemented and expanded. The information is summarized in the new drug specification and gradually supplemented and improved with the development of phase IV clinical trials and further expansion of clinical applications. (4) Pharmacoeconomic evaluation With the increasing demand for health and the dramatic increase in investment in health, there is an increasing tendency internationally to evaluate pharmacoeconomics through clinical trials, and to select inexpensive drugs to reduce capital investment on the premise of ensuring clinical efficacy and safety. Currently, countries such as Canada and Australia have required pharmaceutical companies to evaluate the economics of new drugs in order to support their product license applications.