Objective: Interactions of active pharmaceutical ingredients (API) as well as pharmaceutical excipients don't occur in a pharmaceutical dosage form. Base on structures of paracetamol (PCT) and chlorphenamine maleate (CTM), its combination is possible to give a physical interaction in the solid state. This study was conducted to investigate the physical interaction of PCT and CTM in the solid state.Methods: Characterization used the polarization microscope, solubility test, powder x-ray diffraction (PXRD) to observe peak shifting in 2Ɵ angle, and fourier transform infrared spectroscopy (FT-IR) to examine wavenumber shifting. Results:Results of solubility exhibited an increased solubility percentage with increasing concentration. Polarization microscope analysis presented a combination of crystal morphology after the two substances were mixed in an equimolar ratio. The result of melting point determination of each pure substance was 172 °C for PCT, 132 °C for CTM, and 170 °C for the mixture of the two substances in various ratios. Diffractogram showed the shifting at angle 2Ɵ: 20.715, 19.355-23.500 and 21.840, 26.455-20.330 for concentration ratio of PCT: CTM in (132:0.5) and (330:1) respectively and any change in the functional group was observed from infrared spectrum. Conclusion:All evaluation of PCT and CTM in the solid state has exhibited the interaction in solid condition.