Abstarct: This study was conducted at the Agricultural and Natural Resources Research and Education Center of Semnan Province to investigate the effect of four plant extracts (rosemary, yarrow, sage, bitter olive) and the poison palisine on rice weevil. The experiment had 20 treatments of plant extracts, one treatment of palisine and one control treatment (total 22 treatments) and each treatment had three replications. The experiment was conducted in a completely randomized design. In this experiment, plant extracts with different concentrations were poured into Petri dishes, 10 insects were placed in each Petri dish, and the number of dead insects was counted after 24 hours. Statistical analysis of the results was performed using SAS 9.1 statistical software and comparison of means was also performed at the five percent level. The results of this experiment showed that among the treatments of different extracts of rosemary, sage, yarrow, bitter olive and the palisine poison treatment, the palisine poison treatment had the highest number of deaths (8.7 out of 10). Also, the results of the comparison of the averages showed that the lowest number of deaths was observed in the control treatment, which was equal to zero. After the control treatment, the lowest number of deaths was observed for the rosemary treatments of 50%, yarrow of 50 and 60%, and sage of 50 and 60%. An important point regarding the use of plant extracts is the increase in the effectiveness of these plants on the number of pest deaths with increasing extract concentration. The results of this experiment showed that the highest LC50 among the tested plants was sage extract, followed by yarrow, which was in second place. This indicates that these two plants require a higher percentage of extract to eliminate the pest, but in plants such as rosemary and bitter olive, a lower percentage of extract is required to eliminate the rice weevil pest. In general, baxsed on the results of this experiment, it should be stated that with increasing the concentration of the medicinal plant extract used, the pest killing rate of medicinal plants also increases, which shows that the best dose should be considered for killing. It should also be stated that the LC50 level in various medicinal plant extracts is very important in eliminating pests. In fact, it should be stated that to have a strong and non-chemical pesticide, a plant with a lower LC50 should be selected.