Raw herbs are carefully sourced from selected areas where authentic species of herbs are grown and harvested. Every batch of raw herbs is tested for pesticides and heavy metals. To test for trace amounts of heavy metals state-of-the-art analytic equipment is used such as inductively coupled plasma optical emission spectrometry (ICP-OES). Modern analytical tests include high-performance liquid chromatography (HPLC), gas chromatography (GC) and Thin-layer Chromatography (TLC).