A lipolysis stimulator and a slimming agent which stimulate or facilitate lipolysis of accumulated adipose tissue, to thereby exert the body slimming effect. The lipolysis stimulator or the slimming agent of the present invention contains as an active ingredient any form of a plant or an extract thereof, the plant being selected from among common juniper, togenashi, rosehip, areca, polygala root, plantago herb, calumba, zuikorodoku, garden nasturtium, kidachiumanosuzukusa, bayberry, cogon grass, kohon, shoyokanzo, Japanese white birch, tanjin, kikubafuro, white mustard, common sunflower, ground ivy, Chinese wolfberry, Japanese pagota tree, sennenken, common fig, kankatto, Chinese hibiscus, usubaakaza, fenugreek, English walnut, sozuku, koniwa-zakura, gardenia, shima-kan-giku, akamino-akane, futaba-mugura, karoou, schizonepeta spike, purslane, karabyakushi, and prostrate knotweed.