In this experiment, we treated synoviocytes of RA with curcumol in vitro and evaluated the cytotoxic effects of curcumol on cell viability, cell cycle arrest, signal transducer and activator of transcription (STAT) 1 and STAT3 activities, and protein expressions of phosphorylated Janus kinase (Jak) 2, STAT1, and STAT3. Here, STAT3 is linked to rheumatoid arthritis.