Ants are widespread and relatively harmless although they can cause considerable nuisance when they get into houses.
There are a range of products on the market (available from supermarkets, DIY shops and garden centres etc.) which you can use to treat the ants yourself. Ant powders and gels are the most effective. Gels are less messy, have a longer lasting effect and are more likely to kill off the nest. These products will not kill all the ants instantly, you may have to leave them down for several weeks before the ants disappear completely.
You should only need to seek professional help if you have tried treating them yourself and have been unsuccessful.
At certain times of year, when weather conditions are right, winged ants emerge from the nest. These flying ants will normally only appear for a short period. The best way to deal with them is to open windows to let them out or knock them down with a flying insect spray.