Qalai (Tin) is a silvery white, soft, malleable, ductile, water insoluble and crystalline metal. The medicinal use of Qalai (tin) was reported in the Middle Ages as an agent expelling intestinal worms. It is generally used in Unani Medicine in the form of Kushta (calx). Oral use of raw Qalai is not recommended due to its toxic effects. It is added in the preparation of Kushta after detoxification/purification. In this article entire information regarding temperament, dose, action, uses and toxicity has been incorporated from available Unani literature. Physicochemical standard of Kushta Qalai and its pharmacological, toxicological studies published in different journals have been summarized. This article will be helpful for researchers to conduct further studies.