ʿUyūn akhbār al-Riḍā
Hadith 8181 - وَبِهذَا الإِسنادِ قالَ: قالَ رَسُولُ اللَّهِ صَلَّى اللهُعَلَيْهِ وَآلِهِ: عَلَيْكُمْ بِالزَّيتِ فَإِنَّهُ يَكشِفُ المِرَّةَ وَيُذهِبُ البَلْغَمَ، وَيَشُدُّ العَصَبَ، وَيَذهَبُ بِالضَّنا، وَيُحسِنُ الخُلقَ وَيُطيبُ النَّفسَ وَيَذهَبُ بِالغِمِّ.
31-81 According to the same documentation, God’s Prophet (S) said, “I advise you to eat oil (olive oil) since it will cleanse the stomach, reduce phlegm, strengthen the nerves, eliminate illness, improve tempers, cleanse the soul and eliminate sorrows.”