The present study was undertaken to test the efficacy of 11 commonly available medicinal plants and compare its efficacy in relation to larvicidal and mosquitocidal activities against larvae and adults of Anopheles stephensi (Liston). All the medicinal plants and the mixture were effective against larvae of A. stephensi as evidenced by low lethal concentration and lethal time. The lethality varied in adults and plant extracts of mixture; Eucalyptus globulus, Cymbopogan citratus, Artemisia annua, Justicia gendarussa, Myristica fragrans, Annona squamosa, and Centella asiatica were found to be most effective. Larval mortality between 80% and 100% was observed in mixture treatment, C. asiatica and E. globulus. The adults that emerged from all the treatments were malformed. Further, the treated larvae showed significant decrement in the levels of protein, carbohydrate, and lipids and affect negatively the presence of certain amino acids. The present findings have important implications in the practical control of mosquito larvae and adults in the aquatic ecosystem as the medicinal plants studied are commonly available in large quantities. These plant extracts are easy to prepare, inexpensive, and safe for mosquito control which might be used directly as larvicidal and mosquitocidal agents in small volume aquatic habitats or breeding sites of around human dwellings.