India is a land of stories; haven’t we heard numerous mythological stories since our childhood? Same characters different versions. Gods were the most favourite characters and have been since ages. Various ways to worship the same God in different places are the proof of different stories told in that very state. We have always seen people taking garland of betel leaves and oil for Lord Hanuman. Betel leaves should be made into a garland with a piece of areca nut in each leaf. Have we ever thought why do we do that? Yes! We have and we have different stories for doing so.
A story says that during Ram-Ravana war, Ravana was trying his best to defeat Ram. Hanuman was carrying Ram on his back so Ravana started attacking Hanuman. Hanuman could not be killed but got hurt in the war. Ram made Ravana run out of the battleground, and himself applied oil on the scars of Hanuman to relieve him of pain. This tradition is still followed.
Different story follows for the reason why betel leaves are offered.
After the success in the war against Ravana, Sita Devi spotted hanuman in a betel leaf garden. When Hanuman bowed to her feet seeking her blessings, Sita Devi plucked few betel leaves and showered on Hanuman in order to bless him, so the ritual is still followed.
Another story depicts that when Sri Hanuman conveyed the message from Sri Rama, Sita Devi garlanded Sri Hanuman with betel leaves as a token of her joy and appreciation, as she could not find any flowers nearby.
So these are the various reasons why Lord Hanuman is worshipped with oil and betel leaves.