The side effects of regifenib mainly involve the skin system, blood system, nervous system, and digestive system. Regifenib can cause bleeding, gastrointestinal perforation, gastrointestinal fistula, and other symptoms, which can be life-threatening in serious cases, so you should monitor your blood work and for symptoms such as bleeding or black stools during the use of the drug. Regifinil may cause neurological side effects such as seizures, headache, visual impairment, and blurred consciousness. Regifinil may also cause dermatological reactions such as rash, maculopapular rash, hair loss, and erythema multiforme. Please consult your physician if you should discontinue the drug once it occurs. Regifinil may have serious or even fatal hepatotoxicity, so liver function should be continuously monitored before and during the course of the drug. Once hepatic impairment occurs, patients should immediately consult with a medical professional at a regular medical institution.