A case is presented which highlights the importance of reconsideration of potential differential diagnoses when clinical improvement after therapeutic interventions is lacking. Attention is also directed to the fact that not always the most obvious or even prehospitally established diagnosis is the correct one. In our case report the circumstances pregnancy and seizure were directly linked to the diagnosis of eclampsia but this diagnosis had to be corrected in the later course. This case report highlights the importance of rethinking potential differential diagnoses. A complicating factor was an iatrogenic overdosage of magnesium due to imprecise and confusing drug labeling (g, mg, mmol, mval) which resulted in a cardiac arrest. Furthermore, the neuroprotective effect of magnesium and the positive impact on the outcome in children, as well as the possible cardioprotective effect of magnesium in mothers is demonstrated.