Three doctors attending prayers for Ramadan at Aisha Mosque in Rutter Street, Palfrey, rushed to the 65-year-old's aid when he took ill at about 7.50pm on Monday.
The man, a diabetic, was taken by car to Walsall Manor Hospital by other worshippers following the incident.
Walsall's interim chairman of Union of Muslim organisations, Mohammed Arif, said: "Muslims are going through the fasting month of Ramadan.
"Diabetic people are advised not to fast. We don't know if the gent was fasting, but about 150 people had just opened their fast and were preparing for the sunset prayer.
"When the man collapsed there were three doctors who attended to him."
Mr Arif said the man's sugar level fell and he is now recovering at home after a hospital check-up.