Reactive oxygen species (ROS) are generated spontaneously in cells during metabolism and are implicated in the aeitology of different degenerative diseases, such as heart diseases, stroke, rheumatoid arthritis, diabetes and cancer. In addition to chronic diseases, oxidative stress can also play a fundamental role in the acute hepatoxicity of several drugs, including the world-widely used analgesic and antipyretic paracetamol. Studies have shown that the use of polyphenolic compounds found in tea, fruits and vegetables is associated with low risk of these diseases. Consequently, there is a great deal of interest in edible plants that contain antioxidants and health-promoting phytochemicals as potential therapeutic agents. One such plant is Phyllanthus niruri L. (Euphorbiaceae), which grows to the rainforests of amazon and other tropical areas throughout the world, including the Bahamas, southern India and China. In Brazil, the plant is known as ‘‘Quebra Pedra” which literally can be translated as ‘‘stone breaker”. The plant is traditionally used in Brazilian folk medicine for the treatment of several pathological conditions, including urolithiasis. Uriston, a P. niruri extract has shown high efficacy after extracorporeal shock wave lithotripsy for renal stones. P. niruri has gained world-wide attention due to its effects against Hepatitis B. Recent research on this plant reveals that its antiviral activity extends to the human immunodeficiency virus (HIV). The HIV-1 reverse transcriptase inhibition properties of P. niruri can be obtained with a simple water extract of the plant. Several bioactive molecules, such as lignans, phyllanthin, hypophyllanthin, flavonoids, glycosides and tannins, have been reported in the extracts of P. niruri.