Polyacrylic acid (PAA) blending with lactose or polyol, a lactose derivative, is investigated by Fourier transform infrared, differential scanning calorimetry (I)SC), thermogravimetric analysis (TGA), and stress-strain tests. The IR spectra of PAA/lactose blends exist shifting around 1700 cm and 3400 cm(-1), implying intermolecular hydrogen-bonding interaction between two compounds. DSC data show that PAA and lactose are miscible below 17% lactose. At the higher content of lactose, phase separation occurs due to lactose self-association. Comparing to PAA/lactose blends, PAA/polyol systems show much weaker hydrogen-bonding interaction effect. All blending systems studied exhibit extensive reduction in their thermal and mechanical properties. The result suggests that both lactose and polyol cannot be used as effective additives to enhance the physical properties of PAA.