A 69-year-old female patient was admitted to our emergency service with painful oral ulcers and rectal bleeding. She has been used methotrexate (MTX) because of rheumatoid arthritis (RA). The patient has been used methotrexate every day for 10 days instead of a weekly treatment. Pancytopenia was seen in laboratory tests. Rectal bleeding associated with gastrointestinal mucosal erosion was attributed to MTX toxicity and MTX-induced thrombocytopenia. The direct cause of MTX intoxication in this case was accidental daily use instead of a weekly use. This case demonstrates the importance of communicating adequately with health professionals and emphasizes that MTX should be used weekly. It is essential to describe in detail how the medication can be used and what adverse effects may occur as the result of taking MTX.