To estimate the health risk of mixture of trihalomethanes (THMs) from reclaimed water during toilet flushing, the interaction-based Hazard Index (HIinteraction-based) and the mixture carcinogenic risk (CRM) according to tissue dose were conducted through the integrated use of both the exposure concentrations model and the physiologically based pharmacokinetic (PBPK) model of THMs. Monte Carlo simulations were employed to implement the probabilistic risk analysis and sensitivity analysis. Nine samples were analyzed, which were collected from J Water Reclamation Plant (JWRP) in Tianjin of China. The results indicated that the mean HIinteraction-based (=0.85) was lower than the acceptable risk level (=1). The probability that the HIinteraction-based exceeded the acceptable risk level is 22.97%. For carcinogenic risk, the CRM ranges from 9.41 x 10(-7) to 3.54x 10(-5), with a mean of 5.49x 10(-6). Moreover, the probability of exceeding the acceptable risk level (1 x 10(-6)) is near 100%. And the values of HIinteraction-based from sample no. 1, 5, and 7 exceeded 1, while the values of CRM for all samples exceeded 1 x 10(-6). Consequently, the reclaimed water used for flushing toilets should be paid more attention, though non-carcinogenic effect is relatively small. Furthermore, the concentrations of DBCM had greater impact on both the carcinogenic and non-carcinogenic risk based on sensitivity analysis. (C) 2014 Elsevier B.V. All rights reserved.