four-substance decoction (si wu tang), tonic formula used in Chinese medicine
Definitions (Wiktionary)
noun
a Chinese herbal soup whose ingredients include Paeonia lactiflora (白芍 (báisháo)), Chinese foxgloves (熟地 (shúdì)), dong quai (當歸／当归 (dāngguī)), and chuanxiong rhizome (川芎 (chuānxiōng))