Headache is generally perceived as a negative symptom focused on oneself. However,there are reports suggesting that patients suffering from pain, especially headache, canbe aggressive. The precise nature of the link between headache and aggression is notknown. Here, we describe a homicidal attack, triggered by headache, in a middle-agedman. The patient’s background and the characteristics of the attack suggested a dissociativebehavior. The case shows that headache may be a trigger for homicidal behavior.Case-control studies are needed to determine the prevalence of aggressive tendencies inpatients with headache.