Graft Versus Host Disease (GVHD) is a medical condition that can occur after a person receives a transplant, such as a bone marrow transplant. In this situation, the transplanted immune cells from the donor recognize the recipient's body as foreign and attack it. This immune response can lead to various symptoms, affecting the skin, liver, and gastrointestinal tract. There are two main types of GVHD: acute and chronic. Acute GVHD typically appears within the first 100 days after the transplant, while chronic GVHD can develop later and may last for months or years. Treatment often involves medications to suppress the immune response and manage symptoms.