Irinotecan is known to treat advanced colorectal cancer, and adverse reactions such as vomiting, abdominal pain, constipation, and diarrhea may occur with the use of this drug. Irinotecan can be used to treat advanced colorectal cancer or colorectal cancer that is not effectively controlled by 5-fluorouracil-containing chemotherapy. Adverse reactions to the drug are more complex. The most common adverse reaction to the drug is vomiting, and prophylactic use of an antiemetic such as chlorpromazine is recommended with the drug. In addition, the use of the drug may also occur after abdominal pain, constipation, anemia, leukopenia, thrombocytopenia, pain, infection, rash, hypotension and other adverse reactions, it is recommended to consult the doctor in a timely manner for symptomatic treatment, if the adverse reactions are serious, the drug must be discontinued. Irinotecan can also cause early-onset and late-onset diarrhea. Early-onset diarrhea occurs during or shortly after the end of an IV drip of irinotecan hydrochloride, mostly due to cholinergic effects, is usually temporary and generally not serious; late-onset diarrhea usually occurs after 24 hours of using the drug, and may last for a longer period of time, leading to dehydration, electrolyte disorders, and requires prompt treatment. The drug is contraindicated in cases of inflammatory bowel disease, intestinal obstruction, abnormally elevated bilirubin, severe bone marrow suppression, women in preparation for pregnancy, women during pregnancy, women during lactation. The drug is administered intravenously and oral administration is prohibited. Irinotecan should be used under the supervision of a clinician and unauthorized use is prohibited.