 The following Specific Aims are proposed: 1. Among cocaine-dependent, non-treatment seeking participants, to establish the ability of rivastigmine 3 or 6 mg, daily or HupA 0.4 or 0.8 mg, daily, as compared to placebo, to reduce cocaine-induced craving 0, 20, and 40 mg, IV and to reduce reinforcing effects produced by cocaine 20 mg, IVinfusion. Hypothesis. Relative to placebo-treated participants, treatment with rivastigmine or HupA will reduce cocaine-induced craving and choices for cocaine. 