However, sometimes they can be caused by nothing more than worry or stress. But once they've started, hiccups can be difficult to get rid of.
There are many old wives' tales about curing hiccups, such as frightening the sufferer, drinking water out of the wrong side of the glass, holding your breath or nose, and dropping a key down the sufferer's back.
Personally, I think the two remedies most likely to do the trick are either breathing in and out of a brown paper bag or swallowing a teaspoonful of granulated sugar.
The raw sugar remedy probably works by scraping against the back of the throat and stimulating a nerve to suppress the hiccups, while breathing in and out of a paper bag probably works because it alters the concentration of carbon dioxide breathed in.
Many articles taken from 'A word with the doctor', by Dr. John Windsor.