The U.S. Food and Drug Administration (FDA) seeks applications to develop, implement, and evaluate a human abuse potential (HAP) study of botanical Kratom. FDA has previously warned consumers about the use of Kratom (Mitragyna speciosa), a plant indigenous to Southeast Asia. Kratom alkaloids have demonstrated both affinity and activity at receptor sites known to be associated with abuse, such as mu opioid receptors. Although Kratom use is prevalent, to date, clinical evaluations of its abuse potential have been limited. The proposed HAP study should be performed in accordance with the guidance for industry, "Assessment of Abuse Potential of Drugs," including (but not limited to) the selection of an appropriate comparator(s) and outcome measures, statistical analyses etc. Interested parties, will also complete the submission of an Investigational New Drug (IND) application and obtain Institutional Review Board (IRB) clearance.