Chromolaena odorata (Linn) R.M. King & H. Robinson (Asteraceae) (syn. Eupatorium odoratum L. or Osmia odorata L.) known as Siam weed is a fast-growing perennial, diffuse and scrambling shrub native to Central and Southern America then introduced into the tropical regions of Asia, Africa and the Pacific where it is an invasive weed. Plant grows to 3 to 7 m in height when growing in the open, and it goes by many common names including devil weed, French weed, communist weed, hagonoy, co hoy etc. In Sawantwadi taluka, District Sindhudurg, Maharashtra, it known by commom name Ranmodi. This invasive weed is introduced to many places, either intentionally as an ornamental plant or accidentally, it is now regarded as one of the most harmful weeds present on earth due to its highly invasive and allelopathic nature. Allelopathy is a natural biological observable fact in which neighboring organism produces some biochemicals which persuades all developmental phases and metabolisms of other plants. That biochemical compounds are acknowledged as allelochemicals. It exhibits positive as well as negative allelopathic (detrimental) consequences on the targeted species.