The paper discusses the issue of justifiability and practical value of deciding between a medical complication and a medical error, the subject which has recently been frequently debated among doctors, at court trials and in media. The authors clearly define the meaning of the terms of medical complication and medical error, pointing out that they belong to an entirely different class of terms and further stating that it is not realistic to decide between them in practice. They go on to emphasise that they should be viewed exclusively as obligatory dependent variables. Medical complication may be declared to be a direct consequence of medical error only when forensic and medical expert reports have established a causal relationship between the two. The paper proposes possible causes and circumstances in which medical complications may occur. Special emphasis is given to the fact that not every adverse event or harmful outcome should be automatically identified as medical error. In order to make such identification, all circumstances leading to an adverse outcome need to be clearly established through expert medical expertise. Instead of conclusion, the authors advocate abandonment of existing erroneous concept of deciding between complication and error and the introduction of a new and better concept that views complication as generally undesirable, adverse and harmful consequence while, in order to decide on the occurrence of medical error and possible link with the resulting complication, an objective and thorough forensic and medical expertise on the mechanism(s) and/or causes of the complication is required.