Biejia Jian Wan has 23 ingredients, making this prescription the most complex classical formula on record. It was first mentioned 1,850 years ago in the malaria chapter of Zhang Zhongjing’s formula primer for complex disorders, Essentials from the Golden Cabinet (Jingui yaolüe). The Chinese term for malaria (nüe) literally translates as “miserable torture disease” and technically encompasses a wide variety of infections assailing the nervous system. More specifically, Biejia Jian Wan was originally designed to treat a typical complication of these types of diseases, namely enlargement of the spleen and/or liver following long-standing infection. Over time, the formula evolved to treat all kinds of swellings, enlargements, and masses, especially in the abdomen. While frequently prescribed in patent medicine form in China, true medicinal grade ingredients for this alchemical formula are hard to find. The inclusion of Biejia Jian Wan in the Classical Pearls series of traditional remedies is a commitment to reproduce this rare but effective remedy as close as possible to the original source text, and make it available to the growing number of practitioners who specialize in the treatment of difficult and recalcitrant diseases with Chinese herbs.