The ASA said the advert could discourage people seeking treatment
Vulnerable people with illnesses could have been misled by a preacher's leaflet, the advert watchdog has ruled.
Don Double was described as a "healing evangelist" on a poster and 15,000 leaflets distributed by the All Nations' Church in Cardiff.
The Advertising Standards Authority (ASA) said words like blindness, Aids, and cancer used on the leaflets was "irresponsible".
The church accepted the word "healing" should not have been used.
It said Mr Double would not describe himself as a "healing evangelist" but said staff only noticed the mistake after the posters and leaflets had been used.
The church also said there were far worse adverts in circulation and that no guarantees of success were given in the literature.
The ASA ruled the advert must not be used again in its current form, and warned the church not to include serious medical conditions in its publicity again.
"We considered that some potentially vulnerable readers, in particular those suffering from the listed conditions, might infer that Don Double could offer treatment for those conditions. We therefore concluded that the ad was irresponsible and likely to mislead."
It also said that the advert could discourage sufferers from seeking medical treatment.