This science fair project was performed to find out the effect on plant growth of adding caffeine to the soil. This experiment was done by using Mung bean (Vigna radiata L.) plants, and watering them daily with normal water, water mixed with caffeine bean and with a coffee mixture. Height of plant was measured as a daily parameter to check effect on growth. On fifteen day of germination the plant was removed to evaluate dry weight and spectrophotometric measurement for chlorophyll content. The result of the experiment found that caffeine with low amount gives best results which can be reconfirmed by height, Chlorophyll a, b, carotenoid estimation. The result indicate that mung bean grows faster in soil with caffeine. Another experiment was carried out to show that the effect of nicotine on plant growth fenugreek seeds (Trigonella foenum-graecum) by using cigarette and chewing tobacco. Nicotine is an addictive drug that is found mostly in cigarettes, cigar, chewing snuff. Cigarette and chewing tobacco contain thousands of chemical compounds but nicotine is a major constituent of cigarette and tobacco, kills insect pests and used in many organic insecticides to protect plants. Our study investigated the impact of pure tobacco (chewing tobacco) and cigarette on seed germination of fenugreek. We had three plants of same type and plant them in the same soil and give them same amount of water. One had just water with no nicotine making this plant the control. Second plant had pure tobacco mixed with soil, third plant had cigarette contents mixes with soil. The result showed that if we use cigarette, the plant will grow taller” as compare to the normal plant. But there was significant decrease in germination rate at pure tobacco or at high concentration of tobacco.