Objective: Avicenna (Abu Ali al-Hossein ibn Abdullah ibn Sina) who had a special attention toward diseases treatments, gathered results of ages of herbal medicine experiments on humans and animals in his book “Al-Qānūn fī Ṭibb” or "The Canon of Medicine", which is a reliable book in Iranian traditional medicine. The aim of this research was to build a reliable list of plants effective against liver and spleen diseases, based on Avicenna's book (volume 2). Materials and Methods: By studying the monographs, introduced agents that have been effective in liver and spleen diseases were identified. Upon their origin and effectiveness in diseases of the liver, spleen or both, treatments were organized. Results: From a huge number of drugs, 163 plants from 73 families were found to be effective in treatment of liver and spleen illnesses. In addition, 30 non-herbal agents effective in treatment of liver diseases were detected. The Lamiaceae family have the most effective herbs for treatment of diseases of the liver, spleen or both. Hemp Agrimony, Irsā, and Fūdhanj achieved the highest scores. Conclusion: The effects of different plants on liver and spleen diseases were indicated in Avicenna's book. Due to the report on the above book, further studies needed specially on the effect of Irsā (Iris ensata) and family Lamiaceae on liver and spleen diseases
