Crohn’s disease is mostly related to the environment, genetics, infection, immunity and other factors, and the initial main symptoms are categorized into digestive system symptoms and systemic symptoms. 1. Digestive system symptoms: the most common digestive system symptoms are abdominal pain and diarrhea. The pain is mostly seen around the umbilicus or in the right lower abdomen, mostly intermittent spasmodic pain, mostly aggravated after eating. Patients with diarrhea is intermittent in the early stage, with the development of the disease can become persistent. 2. Systemic symptoms: most patients will have intermittent low or moderate fever, a small number of patients will be accompanied by toxemia, the onset of patients will also appear malnutrition, mainly manifested as anemia, weight loss. 3. Others: When Crohn’s disease is related to immune system abnormality, it may involve several systems of the whole body, which may cause patients to develop symptoms such as oral ulcers and erythema nodosum. If the above symptoms appear, you should go to the hospital in time to seek medical treatment, and under the guidance of the doctor after confirmation of the diagnosis.