Antibacterial effectiveness of tannin contained in the leaves of plants such as guava is influenced by the concentration of tannins. The higher levels of tannin antibacterial activity will increase. Because of its importance in the treatment of guava leaf, the quality, safety and benefits should be improved through research and development. To improve the quality, safety and effectiveness of guava leaves as a natural medicine Indonesia, standardization needs to be done to the raw material, either in the form or in the form of crude drug extracts or galenic preparations. One of the factors that affect the quality of medicinal plant extracts is the concentration of the solvent used for extraction (Gaedcke et al., 2003)[13]. It is therefore necessary to study to determine the concentration of organic solvent for efficient extraction of tannins from guava leaves extract in order to get good quality.