A total of 98 medicinal preparations, involving 69 species of plants, used by the Siddis of Uttara Kannada in the state of Karnataka is described in this paper based on an ethnomedical field study. The finding includes 40 hitherto unknown medicinal uses of known medicinal plants. Among these, the use of the stem sap of Calamus thwaitesii as an antifertility drug, and the use of the flowers of Ichnocarpus frutescens and the rhizome of Hedychium coronarium in the treatment of diabetes are noteworthy. The knowledge of medicinal plants of the Siddis is distinct from that of another tribe of the same locality, the Gowlis.