The purpose of this study was to identify the utility value with material of natural dyeing and to examine the dyeability and antibiosis of fabrics dyed with Solanum nigrum extract. The results obtained are as follows. First, the color tone of dyed fabrics was tinged with from yellow series to green series, in the chrominance the fabric dyed with Fe mordant was showed the highest value. Second, colorfastness to dyeing showed difference as to mordants, but colorfastness to dyeing except for sunlight colorfastness showed the good colorfastness result on the whole. Third, in the test results of antibiosis, the dyed both cotton and silk fabrics showed the very excellent antibiosis effect for bacteria but showed the insignificant effect for fungus.