The algae Sargassum Petefollum (brown), Laurencia Papillose (red), and Cystoseira Myrica (brown) were used in this study to prepare extracts to improve the biological properties (for diabetic rats). Streptozotocin (STZ), 40 mg/kg rat weight was administered to raise the glucose level of rats. They were given 150 mg/kg of rat weight of the algae extracts under investigation. The injection process resulted in a significant increase in blood sugar from 87.67±  2.05 mg/dl in the control group to 331± 3.74 mg/dl in the diabetic group, Diabetic rat groups induced by STZ resulted in an increase in blood sugar level, and a significant decrease in insulin (0.42 ±0.02µ U/ml). The data showed that the an increase in the lipids profile, liver and kidney functions, and a decrease in activity of antioxidant enzymes compared to the control group, and after treatment with algae extracts used, whether brown or red. The results for all types of algae extracts showed an improvement in the biological properties. The results showed that brown algae (Cystoseira Myrica) had more influence on the biological properties, and decrease in blood sugar level was 203.33±2.87 mg/dl to112.00±6.38 mg/dl in methanol extract of Cystoseira Myrica and a significant increase in insulin (2.82± 0.07µ U/ml) and beneficial cholesterol HDL, was 49.05±3.39mg/dl. Also, cleared a significant decrease in lipids profile, a significant decrease in liver and kidney functions, and a significant increase in antioxidant enzymes, compared to the diabetic group.  Finally, this study demonstrates the importance of using algae as a natural source of anti-diabetic compounds. Some effective compounds can be extracted and used as diabetes medications.