Objective: In addition to damage to individual and social health, drug abuse can seriously endanger the aquatic environment through access to aquatic ecosystems. In this research, narcotic drugs (methamphetamine, cocaine, morphine, and codeine) in the input and output wastewater, the sludge arising from wastewater treatment in the wastewater treatment plant of Tehran municipality, and the output effluent in one of the hospitals in Tehran (Tehranpars Hospital) have been examined via GC gas chromatography and Solid Phase Micro Extraction. Method: Solid-phase micro-extraction is an equilibrium extraction method through which it is possible to use pollutants in low concentrations and with high sensitivity without using solvents by means of a proper calibration method. Gas chromatography is the analyzer, initially used with SPME, and, to date, many of its applications are based on separation and analysis by this device. Results: The results of this study showed that high concentrations of codeine and morphine exist in urban sewage and the efficacy of treatment plants in removing these contaminants was not significant (elimination percentages were 23% and 43%, respectively). It has also been observed that there is no cocaine in the study samples. Conclusion: The findings of this study have health-medical implications and points.