Lapatinib is a new targeted therapy drug developed by GlaxoSmithKline in recent years, with the English trade name Tykerb. It is an oral tablet that mainly acts on epidermal growth factor receptors 1 and 2 (ErbB1 and ErbB2), and is a dual-target receptor tyrosine kinase inhibitor. ErbB1 and ErbB2 are two common growth factor receptors that are aberrantly expressed in a variety of cancers, and their aberrant expression contributes directly or indirectly to the growth and metastasis of many cancers. Therefore, many novel targeted therapeutic agents target the activity of these two receptors and thus exert anti-cancer effects. For example, trastuzumab (Herceptin), a targeted drug successfully used in breast cancer treatment, mainly inhibits ErbB2 activity; cetuximab, a targeted drug used in colorectal cancer and head and neck tumors, mainly inhibits ErbB1 activity; gefitinib (Eressa, Iressa) and erlotinib (Troche, Tarceva), targeted drugs used in lung cancer, both ErbB1 receptor tyrosine kinase inhibitors. The novel targeted therapy Lapatinib, however, is able to inhibit both ErbB1 and ErbB2 tyrosine kinase activities, which should theoretically have stronger anti-cancer effects in a variety of cancers. Currently, Lapatinib has shown significant therapeutic efficacy mainly in ErbB2(+) advanced breast cancer, with an effective rate of over 30% for monotherapy, even in patients for whom Herceptin treatment is ineffective. The results of an international multicenter phase III clinical study reported at the ASCO annual meeting in June of this year showed that in advanced breast cancer with ErbB2(+), the combination of capecitabine chemotherapy with Lapatinib was able to further improve patient outcomes and reduce the incidence of brain metastases without an increase in side effects. The conference also reported the results of a study confirming that Lapatinib is equally effective in brain metastases from ErbB2(+) breast cancer. This suggests that Lapatinib has important clinical value in breast cancer. In addition to breast cancer, Lapatinib has also shown some efficacy in other malignancies. For example, bladder cancer, kidney cancer, colorectal cancer, lung cancer, etc. These tumors often have abnormal ErbB1 or ErbB2 activity, and the efficacy of Lapatinib may be related to the drug’s inhibition of ErbB1 or ErbB2 tyrosine kinase activity. Lapatinib has minimal side effects, mainly rash, diarrhea, and mild hepatic impairment. Cardiac toxicity occurs in rare patients, but is less frequent and less severe than that of Herceptin, and cardiac function tends to return to normal on its own after discontinuation of Lapatinib. Therefore, the current study results show that Lapatinib has clear efficacy in many malignant tumors, especially breast cancer, with minimal side effects and easy oral administration, which makes Lapatinib have more significant clinical application potential than traditional chemotherapeutic drugs or single-targeted therapeutic drugs, and is believed to bring hope to more cancer patients in the future.