Four deaths related to the drug 4-methylmethcathinone (mephedrone) are reported. Qualitative and quantitative analysis of mephedrone was performed by high-performance liquid chromatography-diode-array detection. Of the four deaths, one was attributed to the adverse effects of mephedrone, with cardiac fibrosis and atherosclerotic coronary artery disease as a contributing factor. A 49-year-old female insufflated mephedrone; analysis disclosed mephedrone in femoral venous blood (0.98 mg/L). The second death was attributed solely to mephedrone. A 19-year-old male took mephedrone as well as alcohol and “ecstasy”; analysis disclosed mephedrone (2.24 mg/L femoral venous blood) and 3-trifluoromethylphenylpiperazine (3-TFMPP). In the third fatality,...