There are many articles present in literature dealing with the difference between the medical error and the complication in indemnification of damage caused by the medical act. It is a very challenging and sometimes even impossible task. The criteria usually used are defined by the accumulated medical knowledge and the complexity of interactions and conditions under which the medical service is provided. Contemporary medicine is reaching increasingly better results aiming to treat the rapidly ageing population. Consequently, the expectations of patients are growing, and sometimes exceeding reality. Ever more aggressive interventions are being introduced for diagnostic and treatment purposes of conditions, recently considered incurative. Some patients inevitably suffer harm from professional mistakes or from the disease course or complications. The difficulties we face when trying to differentiate cause of the harm often lead to misunderstandings in the general public or the public media, and undermine the confidence regarding the public health system. In this article, the difference between medical error and complication in indemnification of damage is discussed in details.