The fast of Ramadan is rigorous, particularly during long summer days when it may be required to resist all food and drink for as many as sixteen hours at a time. This strain may be too much for people with certain health conditions.
The Qur'an instructs Muslims to fast during the month of Ramadan, but also gives clear exemptions for those who may become ill as a result of fasting:
"But if any of you is ill, or on a journey, the prescribed number (of Ramadan days) should be made up from days later. For those who cannot do this except with hardship is a ransom: the feeding of one that is indigent.... Allah intends every ease for you; He does not want to put you to difficulties...." - Qur'an 2:184-185
In several other passages, the Qur'an instructs Muslims not to kill or harm themselves, or cause harm to others.
Prior to Ramadan, a Muslim should always consult with a doctor about the safety of fasting in individual circumstances. Some health conditions may be improved during fasting, while others may possibly deteriorate. If you decide that fasting could possibly be harmful in your situation, you have two options:
If yours is a temporary, not chronic, condition you may make up the fast (a day for a day) at a later time, when your health improves.
If yours is a permanent or chronic condition, you may make a donation in charity in lieu of fasting. The amount should be sufficient to feed one person a day, for each fasting day that is missed.
There is no need to feel guilty about taking care of your health needs during Ramadan. These exemptions exist in the Qur'an for a reason, as Allah knows best what issues we may face. Even if one is not fasting, one can feel part of the Ramadan experience through other areas of worship -- such as offering additional prayers, inviting friends and family for evening meals, reading the Qur'an, or donating to charity.
Additional information is available below for those with specific health concerns. Again, you should always consult with your own doctor to evaluate your individual circumstances.