Sumbul (Nardostachys jatamansi), also known as spikenard, has a long history of use in traditional medicine systems like Ayurveda and Unani for managing stress, anxiety, and related nervous conditions. Historical texts describe its calming properties and its use as a nervine tonic, sedative, and anxiolytic. In Unani medicine, Sumbul is thought to "cool" the brain and help balance emotional disturbances, and it is often prescribed for conditions described as melancholia or nervous debility. In Ayurveda, it is believed to pacify aggravated doshas linked with mental unrest.

Scientific research on Sumbul's stress-relieving properties is limited but growing. Some preclinical studies in animals suggest that extracts of Nardostachys jatamansi may have anxiolytic and sedative effects, likely due to compounds such as jatamansone and nardostachone, which may act on the central nervous system. However, robust clinical trials in humans are lacking, and the evidence mainly comes from animal studies or in vitro experiments. The traditional use is therefore partially supported by early scientific indications but not yet validated by strong clinical evidence. The rating reflects the predominance of tradition, supported by limited preclinical data.