Is it permissible to break the fast in Ramadan due to severe stomach pain, high fever, and vomiting, followed by an improvement in the pain later on?

Illness is an excuse that permits breaking the fast. Breaking the fast is permissible if it is accompanied by clear pain and hardship, or if there is fear of the illness worsening or healing being delayed because of it, or if a healthy person fears contracting an illness by fasting, or if a sick person needs medication during the day that cannot be postponed.

If a sick person breaks the fast only to take medication without hardship, they should take the medication, refrain from eating for the rest of the day, and make up the fast later. If one did not intend to fast from the night and then recovered or their hardship ceased during the day, they must refrain from eating for the rest of the day and make up the fast. Some scholars believe that refraining from eating is not obligatory if the excuse is gone, and making up the fast is sufficient.