Is it permissible to use nail polish prescribed by a doctor for treatment while performing ablution (Wudu')?

If nail polish prevents water from reaching the nails, then ablution (wudu') is not valid with its presence, and it must be removed before performing wudu'. It can be used after the 'Isha prayer or during menstruation. However, if the nail polish is a medicine and a person would be harmed by removing it for every ablution, then it takes the ruling of bandages and splints.