In breast cancer, mutations in the PIK3CA gene encoding the PI3K protein subunit are very common. PI3K is responsible for biological functions such as cell proliferation. Besides that, breast cancer can arise as a result of dysregulation of signaling pathways in receptor tyrosine kinases (RTKs). Standardized breast cancer treatment has effects that can affect mobility, function, and quality of life. Phyllanthus niruri is able to provide antiproliferative effects on cancer cells without having a cytotoxic effect due to the presence of gallic acid in the plant. This study aims to determine the effectiveness of Phyllanthus niruri as an alternative drug for breast cancer and how Phyllanthus niruri works as an anti-cancer agent through molecular docking studies. The structure of gallic acid as a ligand was then carried out by docking with the PIK3CA protein and receptor tyrosine kinase, using imatinib and 4q2 as controls. The docking results showed that Phyllanthus niruri was quite effective in preventing cancer through inhibition of the RTK signaling pathway and quite effective in inhibiting proliferation through inhibition of PIK3CA. Keyword: Phyllanthus niruri, gallic acid, receptor tyrosine kinase, PIK3CA, docking