Summary. Juvenile idiopathic arthritis remains one of the most common chronic inflammatory rheumatic diseases of childhood. A significant proportion of patients experience nausea, vomiting, abdominal pain and loss of appetite with methotrexate therapy, which can significantly complicate the course of the disease. The aim was to study the clinical and anamnestic signs of liver disorders in children, depending on the manifestations of juvenile idiopathic arthritis. Materials and methods of research. The presence of gastrointestinal complaints, namely abdominal pain, loss of appetite, nausea and vomiting in 104 children with juvenile idiopathic arthritis who were treated at the State Institution "Institute of Child and Adolescent Health of the National Academy of Medical Sciences of Ukraine" was analyzed. Results. According to the results of the study, children with juvenile idiopathic arthritis had gastrointestinal complaints in 47.12%. We find out that the majority of children had gastrointestinal complains at the age of 10–13 years (55.36%, p ˂ 0.001), and at the onset of the disease after 15 years (100%, p ˂ 0.01). Young children often complained of abdominal pain and vomiting, older children complained of loss of appetite and persistent nausea, regardless of the variant, activity, duration of arthritis and the presence of methotrexate in complex therapy. It was also found that appearance of gastrointestinal complaints were observed more often at a dose of methotrexate less than 10 mg / m2 / body surface (p ˂ 0.05). Conclusions. 1. We find out that in 47.12% children with juvenile idiopathic arthritis had gastrointestinal complaints, aged 10–13 years (55.36%; p ˂ 0.001). The most amounts of complaints were common for patients older than 15 years old (p ˂ 0.01). 2. The nature of the complaints varied and depended mainly on the age of the patients. Younger children had abdominal pain and vomiting simultaneously older children had decreased appetite and nausea. The presence of complaints did not depend on the variant, activity and duration of the juvenile idiopathic arthritis. 3. According to our study complaints were not due to the presence of methotrexate in combination therapy. Children complained much more often if methotrexate dose was less than 10 mg / m2 than in the case of higher doses (p ˂ 0.05).