HIT is a comprehensive and fully curated database to complement available resources on protein targets for FDA-approved drugs as well as the promising precursors. It currently contains about 1,301 known protein targets(221 proteins are described as direct targets) derived from more than 3,250 literatures, which covers about 586 active compounds from more than 1,300 reputable Chinese herbs. The molecular target information involves those proteins being directly/indirectly activated or inhibited, protein binders, and enzymes whose substrates or products are those compounds. Detailed interaction values such as IC50 and Kd/Ki are collected if possible. Those up or down regulated genes are also included under the treatment of individual ingredients.