Three types of isoquinoline alkaloids were tested for antimicrobial, cytotoxic, anti-malarial, anti-oxidant, and anti-HIV activities, as well as inhibitory activity against Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells. N- or O-Geranylation contributed to increased potency in four types of activities except anti-HIV and anti-oxidant. Some types of alkaloids may be useful as lead compounds for developing potential chemotherapeutic agents. N,N-Geranylated salsolinol was significantly active in three different assays, antimicrobial, cytotoxic, and EBV-EA, and may be a most useful compound.