One of the important products of date palms is date syrup. Date syrup locally known as “debs" is probably the most common derived date product. The present work was done to evaluate the antioxidant capacity as well as the biological effects of date syrup locally known as “debs" on streptozotocin-induced diabetic rats and to investigate the microbiological changes occurring during the storage of jam containing debs replacing sucrose. The results of phytochemical screening showed that “debs" contains different constituents such as flavonoids, phenols, steroids, and saponins that could be effective as antioxidant and antimicrobial substances. The results also revealed that “debs" has high antioxidant capacity. For the biological study thirty six healthy adult Albino male rats were used. The data collected for blood glucose levels indicated the antidiabetic effect of debs. The results of the microbiological study revealed that the addition of date debs instead of sucrose resulted in the decrease of microbial load in jam upon storage up to three months.