Although e-cigarettes were not designed for use with THC extracts, which are more viscous than nicotine e-liquids, there is an abundance of YouTube videos demonstrating how to modify nicotine e-cigarettes for use with THC extracts as well as how to prepare THC e-liquids. There are also prepackaged cartridges with THC extracts that are compatible with e-cigarette batteries. Yet again, the science base has not kept up with the growing use of these products. The investigators currently have no data on THC delivery, pharmacokinetics, and effects of THC vaping with currently marketed e-cigarettes. Further, just as tobacco is mixed with marijuana for nicotinic reinforcement of THC in products such as blunts, it is not inconceivable that THC may also be mixed with nicotine e-liquids when diluting THC extracts. Therefore, it is important to understand the pharmacology and safety of simultaneous intake of nicotine and THC from vaping.