The present study was carried out to investigate the effect of folic acid (FA) on the some biochemical parameters of female rabbit's treated and non-treated with methotrexate (MTX). Twenty female rabbits were divided in to four groups,control group 5 rabbits were received distilled water, (FA) group rabbits were received folic acid at 0.07mg/kg body weight orally, Methotrexate group : 5 rabbits were received methtrexate (0.03 mg/kg body weight orally ) three times a week and (FA) with (MTX) group : 5 rabbits were received folic acid (0.07 mg/kg body weight orally) daily and (MTX) (0.03mg/kg body weight orally)  three times a week. The drugs were given by intubation. The experiment was last for 9 weeks. Blood sample were collected after nine weeks of the experiment to study the following biochemical parametersbilirubin in serum,unbound Iron Binding Capacity (UIBC), Total Iron Binding Capacity (µg/dl), Total Serum Iron and Ferritinconcentration in serum. The results of MTX group reveal high significant decrease (P≥0.05) bilirubin conc. At the same time there is a significant increase in total SI, TIBC, UIBC in this group. The group of animals received FA with MTX showed a good prognosis with health improvement characterized by high significant changes in all studied parameters to return back to their normal values.It was concluded that (FA) is administration with MTX very important to correct these changes and the animals return to normal conditions. More work is needed to study the effects of these drugs on other systems in the body.