Context: The dried fruits of Arctium lappa L. have been used in two forms in traditional Chinese medicine; crude and stir-heating Fructus Arctii. However, its processed product possesses better activity. Objective: In this study, the chemical constituents of both crude and processed Fructus Arctii and their antiproliferative activities were evaluated. Materials and methods: The seven main active components in crude and various processed Fructus Arctii were quantitatively determined using high-performance liquid chromatography (HPLC). According to the actual amount in crude and five processed samples, seven single components were combined as multi-component combinations with six different proportions. The antiproliferative activities of these compatibility component groups were examined using the CCK-8 assay. Results: During the heating process, the proportion of the seven main components changed dynamically. The contents of 3-caffeoylquinic acid (3-CQA), 3,5-dicaffeoylquinic acid (3,5-diCQA), and arctiin (ARC) declined, while the contents of 4-caffeoylquinic acid (4-CQA), 3,4-dicaffeoylquinic acid (3,4-diCQA), 4,5-dicaffeoylquinic acid (4,5-diCQA), and arctigenin (ARG) increased very significantly. Discussion and conclusions: The results also indicated that seven components in the processed samples had higher cytotoxic profiles against HL-60 cells than those in the crude sample. Therefore, the heating process may enhance the antitumor activity of Fructus Arctii by changing the proportion of active components.