The present study documented pharmaceutically important plant resources used in primary health care of ethnic Garo tribes from Eastern Himalayas (Nokrek Biosphere Reserve [NBR], India). In order to document information on medicinal plants and to maximize the collection of indigenous knowledge of Garo tribes, 12 traditional healers were identified using the Participatory Rapid Appraisal approach. Data were collected through open-end interviews with traditional healers, between 2007 and 2011. A total of 157 plant species representing 134 genera and 81 families were found to be commonly used in the treatment of 67 health-problems. More than one-fourth of the plant species were used in the treatment of cough, flu, and cold, which are prevalent ailments in the study area. The leaves, root, rhizome, and tuber were the most commonly used plant parts while decoction was the most common method of drug preparation.