Global increased demand for herbal medicine in recent years has resulted in the raise of concerns over its quality and safety. Tighter regulations and surveillance in many Asian countries have also been imposed in order to protect public’s health interest. The aim of the present work was to screen for possible adulterants including heavy metals, prescription drugs, poisons and steroids contamination in unregistered herbal products claimed to possess desired medicinal values. These products were obtained via enforcement raids from several bazaars in Malaysia and analyzed by means of analytical techniques: GC-MS, HPLC-PDA and AAS. The levels of Hg (≤ 0.30 mg/kg), Pb (≤ 3.41 mg/kg) and As (≤ 0.50 mg/kg) found were below the permissible limits (i.e., 0.5, 10 and 5 mg/kg, respectively), and none of the known dangerous drugs, poisons or steroids was detected. However, all samples were found to contain an undeclared synthetic PDE-5 inhibitor, sildenafil or tadalafil, in medium to extremely high doses while two samples also contained paracetamol. As such, the public is cautioned and should not purchase unregistered herbal products because unsupervised consumption of any synthetic PDE-5 inhibitor in extremely high doses may have serious health implications.