Coagulation and flocculation are the most used methods for removal of turbidity of water. Recently, many studies have focused on the investigation of natural coagulants for this purpose. In view of the fact that extracts of common bean have coagulation activity, this study is concerned with the chemical composition of these extracts and their influence on the coagulation activity. Extraction was conducted with distilled water, 0.5M NaCl and 1M NaCl and total sugars content, proteins, phytic acid and total phenolics content and their coagulation activity were determined in the obtained extracts. These experiments confirmed that an extraction time of 10 minutes is sufficient for the extraction of active coagulant components from common bean seeds and that water is satisfactorily efficient and most economical solvent.