Saikosaponin A is a triterpene saponin found in Bupleurum that exhibits anti-inflammatory, analgesic, neuromodulatory, anticancer, and immunosuppressive activities. Saikosaponin A decreases production of TNF-α, IL-1β, and IL-2 and increases mechanical withdrawal thresholds and thermal withdrawal thresholds in animal models of chronic constructive injury. Saikosaponin A also decreases self-administration of cocaine and morphine. In colon carcinoma cells, saikosaponin A causes activation of caspases 2, 3, 8, and 9 and PARP, induces apoptosis, and decreases expression of Bcl-2 and XIAP. Additionally, this compound inhibits the proliferation and activation of ConA-treated T cells, inducing G0/G1 phase cell cycle arrest and decreasing expression of TNF-α, IL-2, and IFN-γ.