Vitex negundo, commonly known as the Chinese chaste tree or Nirgundi, has a long-standing history in traditional medicine systems such as Ayurveda and Unani for the management of backache and musculoskeletal pain. Traditionally, its leaves are used in the form of poultices, oils, or decoctions to relieve pain and inflammation associated with conditions like backache, sprains, and rheumatism.

The rationale behind its use is primarily due to its reputed anti-inflammatory, analgesic, and muscle-relaxant properties as documented in classical texts. The plant is believed to pacify the vata dosha, which is associated with pain and movement disorders in Ayurveda.

Modern scientific validation is limited but not completely absent. Some preclinical studies have demonstrated that extracts of Vitex negundo possess anti-inflammatory and analgesic effects in animal models, which could theoretically contribute to pain relief. However, robust clinical trials in humans specifically addressing backache are lacking. Thus, while there is a plausible scientific basis due to its phytochemical constituents (such as flavonoids, iridoids, and volatile oils), the primary justification for its use in backache remains traditional rather than strongly evidence-based.