The nitrate and nitrite content of four leafy vegetables (parsley, garden cress, coriander, and dill) from different regions of Tehran province, Iran (north, south, east, and west) were determined by spectrophotometer method at 538 nm. The results indicated that the dill had the highest nitrate concentration (402.944 mg kg-1), while the coriander had the highest nitrite concentration (0.672 mg kg-1), and these values were significantly higher than other vegetables (P<0.05). Garden cress had the lowest nitrate and nitrite concentrations, 288.556 and 0.378 mg kg-1, respectively. The estimated daily intake (EDI) and target hazard quotient (THQ) of both nitrate and nitrite were below the standard threshold. The EDI values for nitrate were 0.2216, 0.1980, 0.1746, and 0.1587 (mg kg-1 body weight/day) for dill, coriander, parsley, and garden cress, respectively, indicating that the health risk associated with consuming these vegetables was lower than the standard limit (3.7 mg kg-1 body weight /day). The THQ results for nitrate and nitrite samples revealed that they were all lower than 1, implying that the risk level is acceptable for chronic risk health exposure to leafy vegetables. In conclusion, our results showed that the studied vegetables were safe to consumption based on nitrate and nitrite concentrations. تفاصيل المقالة