Praise be to Allah, and may Allah’s peace and blessings be upon the Messenger of Allah, his family and his companions.   Wa alaikum assalam wa rahmatullahi wa barakatuh.   As to what follows:   In response to your question, we say:       There is no problem for a fasting person if he uses oils whether they are medical, moisturizing or beautification oils. This does not affect the validity of fasting, even if they enter the skin, because what is prohibited for a fasting person is eating and drinking. As for the fact that the pores of the body take in some of the oil whether it is medical, or a moisturizing oil like in instances of dryness of the skin, or a beautification oil; this does not affect the validity of fasting, because using these oils is not eating or drinking, and if that is so, then where is the proof that they break fast?  Therefore, it is permissible for a fasting person to use these oils on all parts of his body. Even if  fasting people need to moisten their lips because they are cracked and so on, there is no problem if they use these oils. A fatwa to this effect has been issued by  a group of scholars including Shaykh ‘Abdul ‘Aziz ibn Baz and Shaykh Muhammad ibn Salih al-‘Uthaymin (may Allah have mercy on all of them).