Arsenic trioxide is a chemical compound with the formula As2O3. It appears as a white or yellowish powder and is primarily used in the production of glass and as a pesticide. In medicine, it is known for its role in treating certain types of cancer, particularly acute promyelocytic leukemia (APL), where it helps induce remission. This compound is highly toxic and can pose serious health risks if ingested or inhaled. Exposure to arsenic trioxide can lead to symptoms such as nausea, vomiting, and abdominal pain. Due to its toxicity, strict regulations govern its use and disposal to protect human health and the environment.