Perhaps because religious worship is often supposed to be a time of undistracted contemplation, having bad breath in a place of worship can be problematic. Some religions either currently caution against or formerly forbade having halitosis in their houses of the holy.
On his question-and-answer show Islam Mail Box, television personality and Muslim chaplain Yusuf Estes recently addressed how his faith deals with bad breath. He said that the Q'uran states that after eating onions or garlic, one should not go immediately to a mosque. Estes quoted from memory a passage which explained that "what offends the children of Adam offends the angels of mercy."
He added that while onion or garlic breath is quite taboo in his religion, bad breath resulting from fasting - such as for Ramadan - may actually be looked upon as a good thing.
Onions and garlic are two very common sources of food-related halitosis. The smell of garlic comes from allyl methyl sulfide, a volatile sulfur compound that can leave a powerful smell on the breath. Onions cause halitosis with a similar molecule.
To eliminate bad breath before worship or at any other time, individuals may consider brushing thoroughly and using a specialty breath freshening rinse, tablet or gum.