S,S-Tetrandrine is a benzylisoquinoline alkaloid originally found in Stephania that exhibits anti-inflammatory, anti-allergic, analgesic, neuroprotective, cognition enhancing, anti-depressant, anti-osteoporotic, antiviral, and anticancer chemotherapeutic activities. Tetrandrine is a Ca2+ channel blocker; it inhibits mast cell degranulation and suppresses LPS-stimulated expression of COX and inflammatory cytokines, preventing hyperalgesia in animal models. Tetrandrine also inhibits neurological deficits, decreases infarct size, and suppresses brain edema in animal models of cerebral ischemia/reperfusion. Similarly, this compound inhibits amyloid-β (Aβ)-induced memory and learning impairments in animal models of Alzheimer’s disease. In cellular and animal models of osteoporosis, tetrandrine inhibits osteoclast differentiation and prevents decrease in bone mass. This compound decreases immobility time in the forced swim test and tail suspension test and increases levels of BDNF, 5-HT, and NE in the hippocampus of animal models. In gallbladder carcinoma cells, tetrandrine induces S phase cell cycle arrest, alters the Bcl-2/Bax ratio, induces apoptosis, and inhibits proliferation. Additionally, this compound induces regression in animal models of chromic myelogenous leukemia (CML), decreasing levels of Bcr-Abl and β-catenin. Tetrandrine also prevents Ebola virus infection in animal models.