Olive leaf extract is an herbal supplement that has been proven effective in relieving constipation, according to WebMD.The supplement may also have antiviral and antioxidant capabilities, according to Drugs.com. However, as of 2015, research into the supplement is lacking.
Early experiments in animals showed that olive leaf extract showed an antioxidant behavior in rabbits induced with diabetes, states Drugs.com. Other very early research has shown that olive leaf extract behaved as an antibiotic when used against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and other species of bacteria. Experiments in animals suggest antiviral activity as well; however, research is still ongoing.