**3.1. Chinese medicines and their active compounds for preventing liver cancer**

From a TCM point of view, a good doctor should prevent and cure potential disease in the initiating stage. "Treating before getting illness" is one of the preponderant thoughts of TCM in dealing with disease and health. It is important to prevent the occurrence of liver cancer by keeping healthy diet and lifestyle according to the TCM theories. As we have discussed earlier, spleen deficiency may cause the occurrence of liver cancer. Symptoms such as ascites and abdominal distention are all related to spleen deficiency. According to the relationship among the TCM five internal organs (heart, liver, spleen, lungs and kidneys), the spleen and the liver can influence on each other. Therefore, spleen deficiency can also restrict the liver function. In order to strengthen spleen health and protect liver function, people should avoid taking too much spicy and "cold" food such as pepper, green beans and cold water. Alcohol beverage can also induce spleen deficiency by aggravating the dampness in the body. But moderate drinking are beneficial for preventing liver diseases such as liver cancer according to TCM theories [12].

Many Chinese medicines (CMs) and its active compounds are effective in reducing inflam‐ mation as confirmed by modern science [13, 14]. Recent studies have demonstrated that inflammation is a major stimulus for hepatic carcinogenesis and some CMs may prevent liver cancer by inhibiting inflammation in liver. Xiao Chai Hu Tang (XCHT) is an herbal medicine formula used in some Asian countries for treating chronic viral liver diseases. According to the TCM theories, XCHT can modulate Qi activity and balance between Yin and Yang. Recent studies found that XCHT can prevent chronic hepatitis C‐related liver cancer by suppressing inflammation and inhibiting fibrosis in the liver [15]. Shi Quan Da Bu Tang (SQDBT) is a classic TCM herbal diet formula that was documented in the "Tai Ping Imperial Grace Formulary" in Song dynasty. In TCM, SQDBT were used to regulate Qi and treat Yang deficiency. Modern scientific research show that SQDBT can relieve chronic viral liver diseases by reducing inflammatory processes and controlling serum alanine transaminase (ALT) levels, thus it may prevent liver cancer development [16]. Other TCM herbal extracts or isolates such as the Salvia Miltiorrhiza extracts, Schisandra chinensis extracts, silymarin, glycyrrhizin, baicalein and baicalin may prevent liver cancer by relieving chronic liver diseases associated hepatic steatosis and fibrosis [17–21].
