Narcotics abuse and addiction have been turned to a major problem in the communities. Addiction to any type of narcotics is known to be followed by side effects both physically and psychologically. One way to control addiction is the use of another maintenance medication. The current research paper aims at investigating the effect of one such a drug as methadone on the serum levels of Alkaline phosphatase, Alanine aminotransferase, Aspartate aminotransferase enzymes. A total number of 28 male adult Wistar rats were completely haphazardly assigned to four group (n=7): a control group that received an ordinary daily dietary regime and Experimental groups one, two and three that were administered through oral gavage with 5mg/ml, 20mg/ml and 40mg/ml of methadone syrup, respectively, on a daily basis besides the ordinary dietary regime for eight weeks. Blood samples were collected from the animals at the beginning and at the end of the study for the determination of serum levels of alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase enzymes. In the end, the data were analyzed via taking advantage of one-way variance analysis (one-way ANOVA) and TUKEY Test. The serum levels of all three ALT, AST and ALP enzymes were significantly increased in the groups that had been given different doses of methadone (P < 0.001). According to the results obtained herein and the effects that methadone has on the elevation of liver enzymes levels and also due to the fact that this maintenance medication is being increasingly administered on a daily basis for the treatment of addiction to various narcotics, it seems that there is a need for devising better strategies and better planning for the amount and method of methadone use as well as the way this medication has to be distributed within the society
