When entering into treatment contracts, provisions regarding important details may be missing, as these agreements are often concluded as a result of implied conduct. In the event of a dispute, applicable facts must be determined in detail, whereby the content of the mandate in accordance with Art. 396 CO depends on the nature of the business to be attended to. For physicians, this means that they owe the patient careful treatment according to the rules of medical art (lex artis), aimed at restoring her or his health. However, the physician is not liable for the restoration of health itself, but only for appropriate, professional treatment (lex artis).

With regard to liability, different categories must be distinguished. Private physicians are liable for damages caused by a breach of duty of care having a causal connection to that damage. For public hospitals (and their physicians) cantonal state liability is applicable, however depending on the unlawfulness of the damaging intervention. In the case of treatment damage due to lack of experience of the (assistant) physician performing the treatment, the burden of proof for the (lack of) connection between the increase in risk and the damage lies with the (assistant) physician.

For medical interventions to be justified, the patient’s consent is required, which must be based on a professionally sound and complete explanation of the intervention and its consequences. In the absence of legally binding consent or insufficient patient information, any intervention on the patient’s body constitutes actual bodily harm, which is a criminel offense and usually leads to liability of the performing physician for all risks of the intervention.

It is important to note that liability law for public hospitals is regulated by the Cantons. Most Cantons have introduced original and strict state liability, where claims must be made directly against the Canton or Municipality. But despite this causal liability, the burden of proof for treatment errors (breach of lex artis) and the connection between such error and the resulting damage lies with the patient.