The present study on the Allelochemicals of Eclipta alba: Their role and impact on some selected crop and weed plants. The selected crop plant are O. sativa and P. aureus and weed plants selected are C. sophera and C. tora. The study has been undertaken with aqueous extract of E. alba, Rhizosphere amended soil, Powder amended soil and Activated charcoal amended soil. The plant E. alba belongs to the family Asteraceae is a small branched annual herbaceous plant, grows commonly in moist places as a weed all over the world. In addition to various medicinal properties of the plant, it also shows the allelopathic effect.