Green tea catechins are polyphenolic compounds that exhibit hallmark anti-inflammatory, antioxidant, and anti-arthritic properties especially epigallocatechin-3- gallate the major and the most abundant green tea catechin. The main goal of this study is to evaluate the role of catechins extracted from green tea on hematological abnormalities and impairments of both liver and kidney functions because of rheumatoid arthritis complications. In this study hot water extraction method was used for high-yield catechin separation, the crude extract was introduced to silica gel column chromatography for purifications, and the obtained catechin was detected by spectrophotometric assaying tests and FT-IR. Complete Freund's adjuvant was used for in vivo arthritic induction. The results showed that green tea catechins enhanced anemic conditions associated with chronic diseases like rheumatoid arthritis, raised the erythrocyte count, and reduced leukocytosis. Catechins also improved the liver functions of rheumatoid arthritis rats as working by reducing the serum level of liver enzymatic biomarkers alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) from 51.37 ± 3.12, 82.07 ± 4.11 and 37.52 ± 4.06 to 44.65 ± 5.053, 41.7 ± 6.84 and 27.61 ±5.83 respectively. They also had a good impact on decreasing the abnormal rise of rat's sera levels of both urea and creatinine as biomarkers of kidney function. These observations indicate good therapeutic efficacy of green tea catechins on systemic effects of rheumatoid arthritis rats.