Background: Indigenous knowledge has become recognized worldwide not only because of its intrinsic value but also because it has a potential instrumental value to science and conservation. In Nepal, the indigenous knowledge of useful and medicinal plants has roots in the remote past.
Methods: The present study reviews the indigenous knowledge and use of plant resources of the Nepal Himalayas along the altitudinal and longitudinal gradient. A total of 264 studies focusing on ethnobotany, ethnomedicine and diversity of medicinal and aromatic plants, carried out between 1979 and 2006 were consulted for the present analysis. In order to cross check and verify the data, seven districts of west Nepal were visited in four field campaigns.
Results: In contrast to an average of 21-28% ethnobotanically/ethnomedicinally important plants reported for Nepal, the present study found that up to about 55% of the flora of the study region had medicinal value. This indicates a vast amount of undocumented knowledge about important plant species that needs to be explored and documented. The richness of medicinal plants decreased with increasing altitude but the percentage of plants used as medicine steadily increased with increasing altitude. This was due to preferences given to herbal remedies in high altitude areas and a combination of having no alternative choices, poverty and trust in the effectiveness of folklore herbal remedies.
Conclusion: Indigenous knowledge systems are culturally valued and scientifically important. Strengthening the wise use and conservation of indigenous knowledge of useful plants may benefit and improve the living standard of poor people.