Vata Gajendra Singha (VGS), an Ayurvedic preparation, is used in traditional medicine to treat rheumatoid arthritis in the rural population. The effect of chronic administration of Vata Gajendra Singha (VGS) on the hematological parameters was studied. The acute test of VGS recorded no death, even at the highest dose of 80 ml/ Kg body weight. During chronic testing, the animals were divided into three groups. The first two groups were given VGS preparation at a low dose of 50 mg/kg and a high dose of 400 mg/kg for 28 days, while the third group that served as the control received water for the same period. After 28 days of chronic administration of the VGS preparation, some hematological parameter changes were noted. There were notable changes in the percentage of neutrophils, lymphocytes, Mean Corpuscular Hemoglobin, and platelets attributed on the high and low dosage of Vata Gajendra Singha. These hematological parameters are some important factors related to a variety of disease conditions. Vata Gajendra Singha negatively affect some hematological parameters abnormally in treated rats and should not be administered chronically at a higher dose.