Fast food consumption, which has increased among adolescents, has been associated with the risk of cardio-metabolic disorders. However, the effects of short-term high-fat/high-fructose diet (HFFD) on cardiovascular and metabolic parameters in adolescent rats has not yet been evaluated. Also, preventive effects of codonopsis lanceolata (CL) in these rats are unknown. Therefore, we investigated the effects of short-term HFFD consumption on cardiovascular and metabolic factors in adolescent rats, as well as the preventive effects of CL extract. Adolescent rats were fed a 60% high-fat diet plus 10% fructose water for 2 weeks. During this time, CL extract (200 or 400 mg/kg) was administered once daily. Short-term HFFD increased visceral white adipose tissue (WAT) weight, fasting blood sugar (FBS) concentration and water intake in adolescent rats. This diet also significantly increased systolic blood pressure (SBP), heart rate, and phenylephrine-induced vasocontraction. CL extract, however, effectively reduced visceral WAT weight, FBS, SBP and heart rate in short-term HFFD-fed adolescent rats. These findings indicate that exposure to HFFD for only 2 weeks induced cardiovascular and metabolic alterations in adolescent rats and that CL extract is effective in preventing these harmful effects of short-term HFFD in adolescent rats. This work was by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2021R1A2C2004118). * Corresponding author. Keywords: high-fat/high-fructose diet; adolescent; codonopsis lanceolata ; prevention; visceral white adipose tissue; fasting blood sugar; systolic blood pressure