1, late discovery of the disease, once found to have formed pleural hypertrophy, adhesions, parcels and other foci coexisting, the difficulty of treatment; 2, stopping medication too early: some patients think that the pleural fluid absorption is a cure, so in the pleural fluid disappeared after the drug, the result of the disease repeated and become re-treatment; 3, the use of medication during the side-effects of the treatment, or insufficient treatment, the recurrence of the disease or drug resistance; 4, frequent changes in the program: the treatment period due to the slow absorption of pleural fluid or some discomfort, think the program is not reasonable and keep changing drugs, add drugs, reduce drugs or even stop drugs, which is easy to form a recurrence and drug resistance; 5, hormone application is unreasonable, or the application of irrational, add drugs, even stop drugs. Frequent change of program: during the treatment period, due to slow absorption of pleural fluid or some discomfort, the program is considered unreasonable and keep changing drugs, adding drugs, reducing drugs, or even stopping drugs, which is easy to form a relapse of the treatment and drug resistance; 5, irrational application of hormones, or too long a period of time, or stop too quickly, or after stopping the recurrence of the disease, and a large amount of pleural fluid again; 6, the addition of traditional Chinese medicine is too late to form parcels, adhesion, hypertrophy, which makes it more difficult to be treated; 7, no follow-up drug treatment after pleural surgery, which results in the recurrence of disease or resistance; 8, no subsequent drug treatment after surgery. No follow-up drug treatment after surgery, resulting in repeated condition.