For the prevention and treatment of cancer, including lymphoma, you want to increase the concentration of antioxidants in your body. Olive leaf extract contains high levels of polyphenolic compounds and flavonoids, both of which improve your body’s immune function and neutralize free radicals. Research has also shown that olive leaf extract is able to prevent the growth and spread of tumors, which is why it’s so effective in the treatment of lymphoma. Again, this extract should be taken in conjunction with a more formal treatment regimen for lymphoma from an oncologist.