Several controversies persist about the beneficial or toxic effects of garlic. The present study was undertaken to determine the effects of high dosage garlic according to its mode of administration in rat. We studied the ability of high dosage garlic to modulate kidney antioxidant status when administered either orally (PO) or by intraperitoneal (IP) route. In renal tissue homogenate, PO garlic was antioxidant as it decreased malondialdehyde (MDA), protein carbonyl, free iron and hydrogen peroxide (H2O2) and increased antioxidant enzyme activities as peroxidase (POD) and superoxide dismutase (SOD). IP garlic was pro-oxidant as it increased protein carbonyl and H2O2, has no effect on MDA but unexpectedly increasedcatalase (CAT) activity and decreased POD and SOD activities. In plasma compartment, PO garlic has no effect on creatinine and urea levels whereas IP treatment increased them. High garlic dosage is safer when PO administered. Key words: Garlic, kidney, redox status, administration mode, lipoperoxidation, protein carbonylation, free iron, hydrogen peroxide, antioxidants enzymes.