The chronic toxicity of the Dunaliella salina microalgae was examined to evaluate its toxicity by the exposure of laboratory animals to high doses of Dunaliella salina and to estimate the possibility of using it as a safe supplement. Different hematological and biochemical analysis including complete blood picture (CBC), liver function enzyme activities; aminotransferases (ALT and AST), alkaline phosphatase (ALP), total bilirubin, kidney function tests; urea, creatinine, and albumin, as well as blood glucose level, were measured. The histopathological investigation was also carried out on hepatic, renal and cardiac architectures to examine its safety. Treatment with the dose 100 mg /kg body weight of D. salina powder daily for three consecutive months did not show any signs of toxicity in both genders and in mice and rats (no mortality, no hair loss, no diarrhea, no patches of yellow color appearance, etc…..). Moreover, abnormalities on behavior, food and water intakes and health status among the treated animals were not observed. CBC profile revealed a significant increase in hemoglobin (Hb) level in treating male and female mice and rats compared to their related control levels. The biochemical analysis clearly showed an insignificant change in liver enzyme activities, blood glucose level at a dose of 100 mg/kg. Also, an insignificant reduction in total urea and creatinine levels in both genders of mice and rats were noticed. Histopathological investigation showed normal architectures of all organs. Hence we can conclude that Dunaliella salina has been proven a safe profile up to 100 mg/kg body weight, however, it succeeded to stimulate the Hb synthesis compared to control groups, showing its benifits to be used safely as food additives or protective and curative agent in different diseases in future.