Medication-overuse headache affects 1 to 2 percent of the population. Any kind of painkiller, if taken regularly at least 10 days per month can cause medication-overuse headache, and therefore the possibility of this headache has to be raised whenever a patient with a preexistent headache notices a significant increase in headache frequency during a period of frequent painkiller consumption. Medication-overuse headache is most prevalent in females between 40 and 50 years of age. Its main risk factors are smokig, obesity, depression, and anxiety. The pathomechanism of medication-overuse headache is complex, with a probable genetic propensity and other biological (neurochemical and neurophysiological), as well as psychological and behavioural factors (such as anticipatory anxiety, catastrophisation of pain and consequentially a compulsive painkiller use) contributing to its genesis. The prerequisite of successful treatment is the withdrawal of the overused substance, other necessary elements of the therapy include the treatment of withdrawal symptoms including rebound headache, the introduction of an effective preventative therapy, taking into consideration the highly prevalent comorbid disorders as well, and the education and psychological support of patients. As the relapse rate can be as high as 30 to 40% regardless of effective treatment, the prevention of medication-overuse headache is of paramount importance, and the role of general practitioners can hardly be overstated.