AbstractObjectiveTo evaluate the antimicrobial and toxicological effects of aqueous garlic (Allium sativum) bulbs extract in wister rat using biochemical and hematological parameters.MethodsA total of 20 wister rats were assigned into four (A–D) groups of five animals each. Group A served as the control and was administered 1 mL of distilled water. Groups B–C were given 300, 600 and 1200 mg/kg body weight of garlic (Allium sativum) bulbs extract for 5 weeks.ResultsGarlic bulbs extract produced significant inhibitory activities against all bacteria tested at concentrations of 120 and 160 mg/mL. However, at concentration of 80 mg/mL, the extract had no inhibitory activities against Klebsiella pneumoniae and Salmonella typhi. The minimal inhibitory concentration and minimal bactericidal concentration ranged between 80–120 mg/mL and 120–160 mg/mL respectively. Toxicological study revealed that the extract did not cause any significant (P > 0.05) alteration to serum aspartate transaminase, alkaline phosphatase activities, total bilirubins, Na, K, creatinine, red blood cell, hematocrit, hemoglobin, mean corpuscular hemoglobin concentration, granulocyte and organs-body weight ratio. However, serum alanine transaminase activities, total proteins, direct bilirubins, Cl− concentrations and body weight gain were significantly (P < 0.05) lowered while the concentrations of urea, albumin, white blood cell, mean corpuscular hemoglobin and mean corpuscular volume count were raised significantly (P < 0.05) in rats dosed with 600 and 1200 mg/kg of the extract. However, at a dose of 300 mg/kg only, the concentrations of Cl−, urea and albumin were mildly altered.ConclusionsThe extract caused selective changes in some biochemical parameters of organ function; however, since only mild alteration was observed at a dose of 300 mg/kg, the garlic bulb may be considered to be relatively safe and could be explored as an oral remedy at this dose.