Our laboratory identified 4 constituents (amentoflavone, quercetin, chlorogenic acid, pseudohypericin) that may be responsible for a decrease in lipopolysaccharide (LPS)‐induced prostaglandin E2 (PGE2) by an Hypericum perforatum (Hp) fraction in RAW 264.7 macrophages. Low levels of constituents in the fraction and studies with combinations of constituents suggested that interactions of these constituents were necessary for the reduction in PGE2. The goal of this study was to investigate the role of the constituents in the gene expression impact of the fraction. Microarray analysis was performed with replications as fixed blocks and treatment (Hp fraction, mock fraction of the 4 constituents combined at levels detected in the fraction, solvent control) and LPS (with, without) as factors. With LPS and compared against the solvent control, the mock fraction affected 162 genes and the fraction affected 780 genes; 40 genes were differentially expressed with both treatments. Important pathways for both treatments were the Janus kinase‐signal transducer and activator of transcription pathway and eicosanoid metabolism, among others. Pathways affected only by the Hp fraction were cell cycle and cholesterol biosynthesis, among others. This data verifies the importance of interactions of constituents to explain bioactivity.