Ondansetron is FDA approved for chemotherapy induced nausea and vomiting, postoperative nausea and vomiting and radiation induced nausea and vomiting. Ondansetron has shown efficacy for nausea and vomiting in HIV infected individuals for palliation, as well as for diarrhea due to cryptosporidium infection.(Currow, Coughlan, Fardell, & Cooney, 1997; Gompels et al., 1993; Schworer, Hartmann, & Ramadori, 1994) Until recently, ondansetron's cost was prohibitive. However, as a generic drug it has become more affordable. Among the benefits of this drug is the qualitative benefits for HIV infected individuals with nausea and diarrhea as well as cocaine dependence. HIV medications can cause nausea (M. O. Johnson, Stallworth, & Neilands, 2003; M. O. Johnson et al., 2005; O'Brien, Clark, Besch, Myers, & Kissinger, 2003; Reynolds & Neidig, 2002) and thus adherence might be improved with this medication in cocaine using individuals. Ondansetron is well tolerated in HIV infected individuals, and according to micromedex there are no known drug interactions with HIV medications (Gompels et al., 1993)