Many people fast even though they are very sick because they do not know. But the Shari’ah has made alternative arrangements for them. Again, many do not want to fast on the pretext of a minor illness. But in many cases fasting can be done by taking necessary medicines following the advice of a doctor.
Here it is mentioned:
Injections, insulin or vaccines do not break the fast, and even glucose injections do not harm the fast. (Fatawa Osmani: 2/18)
There is no harm in using eye drops while fasting, although the taste of the medicine is felt in the mouth. (Fatawa Alamgiri: 1/203)
Endoscopy is done to diagnose internal diseases of the body. At this time a pipe is inserted into the abdomen through the throat. If oil, water or any other substance is put in this pipe, then the fast will be broken. And if oil or any substance is not applied, then it will not break the fast. (Raddul Muhtar: 3/369)
Taking oxygen without any kind of medicine while fasting will not break the fast. And if any medicine is mixed with oxygen, then the fast will be broken. (Jadid Fakhi Masael: 1/6)
It is makrooh to push saline on the body in order to remove the weakness of the rosary. However, saline can be taken in the body due to the disease. This will not break the fast. (Al-Islam wa Tibbul Hadith, p. 265). There is no harm in giving or taking blood while fasting. (Fathul Qadir: 4/326)
If the doctor says that due to the disease, the level of the disease may increase due to this fast or the recovery may be delayed, then the fast is broken. But it is not permissible to break the fast due to some common ailments like minor ailments like headache, cold and cough. It should be kept in mind that the fasts which are broken due to the disease should be performed one by one instead of one. If the disease increases during fasting, it is considered inappropriate to observe fasting. In this case it is necessary to break the fast. Allaah says (interpretation of the meaning): “Do not kill yourselves. Surely Allah is ever Merciful to you. ‘ (Surah: Nisa, verse: 29)
Fasting is not necessary for the very old. However, that person will pay the ransom or ransom with someone else. One Miskin will be fed one meal for each fast. In this connection, Allaah says (interpretation of the meaning): (Surat al-Baqara, Ayat: 164)
In case of death of an elderly person or a person suffering from a disease from which he is not likely to recover, a person who is incapacitated will get two and a half ounces of wheat (the amount of fitra) or the equivalent price for each fast. In Islamic terminology it is called fidia. (Zawahirul Fiqh: Volume 1, Page 29)
Using an inhaler breaks the fast. People with Respiratory Diseases: People who need to use inhalers every day should not fast in Ramadan. It is obligatory to make up the missed fasts only after recovering from the disease. However, if you are discouraged from getting healed from respiratory disease, it is necessary to pay fidyah for every fast. If he ever recovers after paying the ransom, he will have to work again, that ransom will not be enough. And if the ransom is not paid before the death, then it is necessary to make a will.
(Addurrul Mukhtar: 2/395, 2/423, Raddul Mukhtar: 2/395, 427, Fatawa Fakihul Millat: 5/445)