Robert Saunders was a surgeon on the British Turner expedition to Tibet in 1783-85. In 1789, Saunders published a description of a mercury processing method for treating 'the venereal disease' that he witnessed at Tashilhunpo. Since Saunders himself used mercury for his patients, the question arises whether he described a Tibetan method of processing mercury or projected his own experiences on what he saw. This paper traces parallels of his description and analyses venereal diseases in Tibetan medical texts. The symptoms described in these texts cannot be easily equated with modern syphilis. This article explores the following questions: How were venereal diseases classified in Tibetan medical texts? Were mercurials mentioned to treat them? Were they intended to cause salivation? In answering these questions, the heterogeneity and exchange of medical practices in Tibet from the seventeenth to the early twentieth century, involving the use of mercury for venereal treatments, becomes apparent.