The effect of aqueous root extract of Manniphyton fulvum (MF) on serum glucose concentration and malondialdehyde (MDA) was investigated in Wistar albino rats treated with bonny light crude oil (BLCO) for 14 days. From the study, oral administration of 5ml/kg body weight of BLCO alone caused a significant (p<0.05) increase in serum glucose concentration and MDA level compared to control (group1). However, oral administration of 170mg/kg body weight of aqueous root extract of MF(group 4) resulted to significant (p<0.05) reduction in these parameters compared to group treated with BLCO alone (group 2). The result obtained from glucose concentration of group 4 was not significantly (p>0.05) different when compared to group1. Administration of 170mg/kg body of the aqueous root extract of MF alone caused significant (P<0.05) reduction in MDA compared to control. The result obtained from this study indicated that combination of high serum glucose concentration and increased oxidative stress in BLCO treated groups caused an array of imbalances and associated toxicity. However, administration of aqueous root extract of MF restored the imbalances and ameliorated the toxic effect of BLCO on these parameters investigated in wistar albino rats.