The safety of phycocyanin pigment extracted from Anabaena oryzae  SOS13 was assessed by administration to Wistar Albino rats as one single dose or repeated doses (0, 50, 100 and 200 mg/kg body wt/day) over 28 days. Acute toxicity assay indicated the safety of Anabaena phycocyanin with the No-Observed-Adverse-Effect-Level (NOAEL) up to 5,000 mg/kg body wt. The changes in body or organ weight in Anabaena phycocyanin receiving rats during 28 days were within normal range of the control. The levels of serum protein and A/G ratio did not indicate any inflammatory or liver impairment and rather referred to ameliorated protein metabolism. SDS-PAGE confirmed that Anabaena phycocyanin have not any toxic influence on the expression of serum proteins or immunity system. The levels of serum glucose in the rats receiving Anabaena phycocyanin did not indicate any toxic effects. The levels of serum urea and creatinine in the phycocyanin receiving rats indicated not only the lack of renal toxic effects but also an ameliorating action on renal performance. Anabaena phycocyanin treatments were associated with insignificant increases in the level of hematological parameters revealed the absence of adverse effects on mature circulating cells, hemoglobin synthesis, white blood cell (WBC) synthesis, blood coagulation and homeostasis.