Dear Doctor, Is it true that worms cause coughing? How often should someone deworm? Gilbert Dear Gilbert, Intestinal worms do cause coughing. Worms like round worm, hook worm and lung fluke are ingested via the mouth due to poor hygiene. The source of infection is contamination either at the level of cleaning, cooking, serving or consumption of food. Unclean hands after gardening, cleaning or handling pets can also transmit worms. The worms reach intestines and multiply. They travel via the blood stream to the lungs and can be swallowed again from the mouth. Their presence in lungs can cause cough. Migration of the worms or their larvae can induce allergy, thus causing cough as one of the manifestations. This occurs due to reaction of the immune system of the body. Presence of worms can also precipitate and aggravate cough in people suffering from allergic bronchitis or bronchial asthma. The eggs of these worms are passed out in faeces and remain viable in soil for a long time. From there, they can be ingested by another person, thus setting a vicious cycle of poor health. These worms not only cause cough but can cause abdominal pain with cramps and frequent diarrhea. They deprive the body of essential nutrients and cause chronic anaemia. Growth of children can be affected due to presence of worms. It is vital to prevent worm infestation through good hygiene in cooking, cleaning, serving and eating. But in spite of all hygiene measures adopted, there is always risk of contamination, particularly in children. Hence it is advisable to deworm twice every year to minimize risk of infestation.