The fragrance of Ketaki stimulates as it relieves the heaviness of feelings of depression.
However, if you worship Lord Shiva, this flower is forbidden as an offering to His Holiness in puja or altar.
Once upon a time, there was a dispute between Brahma and Vishnu as to who may be the most superior amongst the two of them. Brahma announced that he was indeed the best because he was the one recognized for creating the universe. Lord Vishnu considered himself more superior than Brahma because because he considered himself to be the manifestation of all creation.
Then, it was decided between them that whomever would find the most largest Jyotirmaya Lunga first, would be considered the most superior. This was the only way they could determine who was above and higher than the other. Upon this agreement, both Demi-gods departed on their mission to find the very special Linga, heading in opposite directions.
After some time, Vishnu returned without the special Linga in hand nor did Brahma yet, as he was making his way to return back to the meeting ground he happened to glance over and see a Ketaki flower floating down from the tree. Suddenly, Brahma asked the flower to be a false witness and claim that Brahma indeed had found the prized Linga and was now worthy to be the greatest amongst all the gods. When he returned, he announced to Vishnu that he had in fact, found the linga and said that he had reached the end of his pursuit.
In that moment, the Ketaki flower bore witness to Brahma success and affirmed the tale so that he could declare his superiority.
Upon hearing this strange competition and act of deceit, Lord Shiva appeared on the scene and quickly admonished Brahma for his tall tale of untruth declaring that no being in the three worlds would worship him from this day forward.
Lord Shiva then announced, “I am the cause, the originator and the master of the Universe. I have created both of you.” Then, he turned to the Ketaki flower which bore false witness and said, this flower may never be used in honor of me, nor in worship nor praise at any time for me, from this day forward.
And so it be, no Ketaki flower is used on any puja altar where Shiva remains and bestows His blessings to His devotees.