Introduction: Ascorbic acid (AA) is a water-soluble vitamin that is well known for its antioxidant and immune-boosting properties. Owing to the wide-range application of AA in the treatment of numerous ailments and its sweet taste, it is usually abused i.e. overused. However, the effect of the abuse has rarely received attention. Therefore, this study was designed to assess the effect of oral administration of high-dose ascorbic acid on biochemical and haematological parameters as well as the effects on the kidney, liver and lungs. Methods: adult guinea pigs were divided into four (4) groups where group 1 served as the untreated control group and groups 2-4 were dosed with 29 mg, 662 mg and 1258 mg of ascorbic acid per day, respectively for 28 days. Results: the result revealed that administration of high dose ascorbic acid significantly (P<0.05) increased serum creatinine from 50.0 +/- 7.09 (NC) to AA29- 73.8 +/- 4.5, AA-662-89.7 +/- 3.3 and AA1258- 79.9 +/- 5.7mmol/L and urea levels in the treatment group AA-1258 -18.3 +/- 0.5 mu mol/L compared to the normal group (NC-2.15 +/- 0.6 mu mol/L). Disturbance in electrolyte balance was observed with a significant (P<0.05) increase in Na+ from NC- 131.3 +/- 3.5 mmol/L to 135.7 +/- 3.6 mmol/L in the AA-1258 treatment group, Cl- (NC- 67.1 +/- 1.6 mmol/L increased to AA29- 92.1 +/- 0.83, AA662-95.3 +/- 1.3 and AA-1258- 95.6 +/- 0.4 mmol/L), and Ca2+ (NC- 2.66 +/- 0.03 to AA1258- 3.36 +/- 0.03 mmol/L) and a significant (P<0.05) decrease in serum K+ in the AA29-5.0 +/- 0.2, AA662-5.2 +/- 0.3 and AA1258-5.6 +/- 0.3 mmol/L treatment groups compared to the normal group 6.6 +/- 0.3 mmol/L. There was also a significant (P<0.05) increase in the differential blood count in the animals with a significant (P<0.05) increase in red blood count (NC-5.11 +/- 0.13 x 10(6)/mu L to AA1258- 5.75 +/- 0.11x106/mu L), haematocrit count (NC 39.90 +/- 0.52% to AA-29-42.08 +/- 0.24 and AA1258-46.13 +/- 0.86%), white blood count (NC 10.15 +/- 1.01 x10(3)/mu L to AA1258- 15.18 +/- 1.65x10(3)/mu L), total lymphocytes (NC 3.5 +/- 0.51x10(3)/mu L to AA29-5.28 +/- 0.43x10(3)/mu L), monocytes (NC 0.45 +/- 0.07x10(3)/mu L to AA1258 0.80 +/- 0.07x10(3)/mu L), eosinophils (NC 0.23 +/- 0.03x10(3)/mu L to AA12580.40 +/- 0.03x10(3)/mu L), basophils (NC0.68 +/- 0.10x10(3)/mu L to AA12581.20 +/- 0.10x10(3)/mu L) and neutrophil count (NC 4.73 +/- 0.68x10(3)/mu L to AA1258 8.36 +/- 0.71x10(3)/mu L). The histopathological indices indicate cellular necrosis in the AA662 and AA1258 treatment groups of the kidney and liver respectively compared to the normal control which has normal cells. Conclusion: high dose of ascorbic acid can therefore be suggested to cause damage to the cells by causing cellular necrosis as observed in the histopathology results and has effect on the blood cells as observed in the increase compared to the normal control, and the consequences are possibly triggered through inflammatory responses.
