Background and Aim: In determining the responsibility of medical staff, it is essential to formulate a rational system that, while paying attention to the patient's rights and compensating his damages, pays attention to the role of each factor in causing harm to the extent of guilt. This issue is considered important if different factors are involved in causing harm, because firstly, the cases against the medical staff are related to the community of different factors in the occurrence of crime, and secondly, the existence of ambiguities and shortcomings in the legal system. Our country-both in legal regulations and in judicial procedure-has a causal relationship, which has made it one of the most controversial and ambiguous issues in terms of doctrine. Methods: This article is a descriptive and analytical method, while paying attention to the basic rules and principles related to the causal relationship, deals with the responsibility of the medical staff on the assumption of cause and effect community. Findings: The findings of this study indicate that the current law approach is the opposite of the previous laws in order to solve many issues, but in some cases, ambiguities are still observed. Conclusion: When the cause and the director play a role in the occurrence of the damage, the principle is on the guarantee of the director. However, if the cause is stronger than the manager, the cause will be the guarantor. According to the opinions of jurists and lawyers, the guarantee will be given to the nurse,Also, in medical affairs, the claim of the doctor's ignorance is not accepted, whether it is negligence or fault.