RESUMO
It is difficult for the patients with low cure rate to achieve the requirements of the"but for rule"or "preponderance of evidence standard" in the traditional causal argument. In dealing with such cases ,judicial practice has tried to broaden the concept of damage ,and adopt the theories of"loss of chance" ,"expectation infringement theory"or"comparative possibility theory" ,with the purpose to make up for the applicable dilemma of traditional causality. However ,the expansion of the concept of the damage will objectively cause some problems like abuse of rights ,concrete right becoming nothing and even subjective imputation.In the current legal system ,we can analogical apply the rule of joint dangerous act ,and correct the causal relationship to resolve such incidents. It will be more fair and just .