A pharmacological survey of plants from Monteverde, Costa Rica, including 165 species representing 61 families has been carried out. Crude plant extracts have been tested for in-vitro bactericidal and fungicidal activity as well as cytotoxic and anti-herpes activity. Of these, 123 extracts exhibited notable cytotoxicity, 62 showed antibacterial activity, 4 showed antifungal activity, and 8 showed promising antiviral activity. Thus, 101 of the plant species examined in this work, or 62%, showed marked bioactivity in one or more bioassays. These results underscore the phytomedicinal potential of Neotropical cloud forests.