This study is focused on Crohn’s disease, a type of long-term inflammation of the digestive tract. The research involves patients using the medication methotrexate, which is administered either through subcutaneous injection, meaning it is injected under the skin, or by taking oral tablets. The purpose of the study is to understand how the medication builds up in the body over time and how these levels relate to how well the treatment works or if it causes side effects.

During the study, researchers will monitor levels of a specific substance, MTX-PG, in the red blood cells. This substance is a byproduct of the medication that stays in the blood and can indicate how much medicine is actually active in the body. Participants will undergo regular check-ups to track their health and the effectiveness of the treatment over several months.