|JWH-018 and JWH-073 are two main active ingredients of K2. The metabolite identification was challenging because of multiple active ingredients of K2. Also, the positive specimens were from street and there was no control available. To resolve this challenge, JWH-018 and JWH-073 were incubated in human liver microsomes and in vitro metabolite pathway was identified for individual compounds on an accurate mass system. The metabolites from human urine matrix were then identified based on the structure information and metabolite pathway from in vitro studies. The correlation of in vitro and in vivo metabolite pathway was also discussed. A screening method for K2 is developed.