Cause-and-effect relationship is one of the premises of a provider's liability for a hospital-acquired infection. However, the evidentiary difficulties involved in dealing with the damage caused to a patient by a hospital infection are both important and still pose an issue. The legislator has adopted a precise definition in which hospital infection remains in a functional and adequate cause-and-effect relationship with the provision of medical care. In a civil process, the injured person must be able to prove and establish a causal link between the fault of the subject and the injury.

In medical trials, the court may, after considering the circumstances of the case, acknowledge probability to be sufficiently high, without requiring a strict and certain proof of how the organism was infected, because such proof is often impossible to obtain for biological reasons. Therefore, if there is no possibility to prove the cause-and-effect relationship between infection and the damage in the form of disease progression, as a result of the present state of medical knowledge, it should be considered at the level of Art. 6 and Art. 361 paragraph 1 of the Civil Code. The above limitations of the evidence and the nature of the cases in which they occur also result in a specific displacement of the burden of proof. In the case of unrealistic strict requirements, the means by which the infection has entered the body, if the defendant claims that, despite the established condition, the infection is from other sources, the burden of proof is shifted to the defendant, that is, the therapeutic agent.

Key words: hospital infection, cause-and-effect relationship, burden of proof, actual presumption.