Objective: From the previous study, Tom Yum soup caused the discoloration of composite filling materials. The aim of this study is to additionally examine which components of Tom Yum have a direct impact on discoloration of them. Methods: Nine discs (Ø=14mm., H=1.2mm.) of each product (Dyract AP, Spectrum TPH , XRV Herculite) were soaked in distilled water at 37°C for 24 hours before measured in CIE L*a*b* system by spectrophotometer (Hunter Lab, Ultra Scan XE), then soaked in prepared chilli paste solution (4% by w/v) and fish sauce solution (4% by vol) at 50±1°C in 1, 3, 6, 12, 24, 72, 168 and 336 hours and measured of each time. L, a* and b* values were used to calculate the mean values and standard deviation of ΔE in each time interval of each product. The discoloration will be clinically unacceptable when ΔE>3.5 (O'Brien WJ Dental Materials and Their Selection, 1997:29). Results: It is found that Dyract AP had ΔE>3.5 after chilli paste solution exposure for 6 hours (4.72±1.15) while Spectrum TPH and XRV Herculite had ΔE>3.5 after exposure for 24 hours (3.70±0.69 and 3.80±0.95 orderly). After chilli paste solution exposure for 336 hours, Dyract AP had the highest ΔE (30.51±2.04). However, all products still had ΔE>3.5 after fish sauce solution exposure for 336 hours. Conclusion: These can be concluded that chilli paste can cause clinical discoloration of all products while fish sauce can not, and Dyract AP is the most discolorated while Spectrum TPH is the least in both chilli paste and fish sauce exposure.