The use of plant-based insecticides is safer for both humans and the environment. Any insecticide has a negative impact on the growth and metabolic rate of the insect. The toxicity of two bee products (bee venom and propolis) and the commercial oils of garlic, marjoram and anise were tested against the late 3^rd larval instar of Culex pipiens. After 24 h of treatment, the three oils showed larvicidal activity with LC₅₀ of 1323.81, 840.71 and 577.53 ppm for garlic, marjoram and anise, respectively. The metabolic rate change within the treated larvae was estimated through the determination of total proteins, carbohydrates and lipids. Garlic oil significantly reduced protein content from 33.8± 0.98 to 30.4 ± 0.4 mg/g. Marjoram and garlic oils significantly reduced carbohydrate content from 15.76 ± 0.7 to 11.43 ± 0.66 and 11.2 ± 0.7 mg/g, respectively. Anise oil significantly increased lipid content from 3.11 ± 0.21 to 3.57 ± 0.14 mg/g.