Objective: To investigate the effect of OPT (Oral Placement Therapy) on Blood lead levels (BLL) measured in microgram/dl and CARS 2 ST (Childhood Autistic Rating Scale 2nd edition Standard version) scores of autistic children both in the short and long term. It also studied the clinical views in speech, feeding and sensory needs by using OPT to bring down the BLL along with levels of CARS2-ST scores in children under autism spectrum disorder. Methods: This comparative observational study was conducted from April 2019 to January 2020, used repeated measures design involving 40 children under autism spectrum aged between 3 to 8 years with concerns of mouthing and smelling of inedible things.  40 participants were recruited to understand the performance benefits of a 5 months OPT versus 10 months OPT on severity of autism as measured by the CARS2-ST from 5 months to 10 months. An asymp sign test was used to compare the differences in CARS2-ST scores in the two repeat measures.Results: Wilcoxon signed-rank test showed statistically significant median decrease in BLL (7.3) and (6.8) at 5 and 10 months respectively when compared before therapy (7.75).