Ilex paraguariensis.Yerba Mate leaves contain saponins (In fact, one recent study yielded 3 new saponins in the Yerba Mate leaf!) Saponins are phytochemicals that have been found to specifically stimulate the immune system and aid the body in protecting against disease. They possess significant anti-inflammatory properties. The immune system, a critical collection of biological structures and processes, is important to keep as strong as possible. With so many medications being prescribed for immune disorders these days; write yourself off of that e-prescribing program and consider Yerba Mate as a natural way to strengthen your body's defense.