Berberine is the main component of Phellodendron amurense Rupr., a natural yellow colorant. Because of the low substantivity of the cationic dyes to cellulosic fibers, the cotton fabrics are difficult to dye with berberine. 1,2,3,4-butanetetracarboxylic acid (BTCA) and other polycarboxylic acids have been used in durable press finishing of cellulosic fibers. Introduction of carboxylic group to the cellulosic fibers could improve the interaction between berberine and cellulosic fibers. Thus the cotton fabrics treated with polycarboxylic acid could be dyed with Phellodendron amurense Rupr. extract. In this context dyeing behavior and color fastness properties were investigated. Dye uptake increased with increasing concentration of BTCA, but both wash fastness and light fastness were not enhanced. Neutral pH of dyebath resulted in higher dye uptake than acidic or alkaline conditions.