Is it harmful if foreign materials and irritants go down into the lungs?

When things like food slip down into the lungs, this is called 'aspiration.' Aspiration can be a serious problem, because the food can cause inflammation in the lungs, leading to chronic breathing problems. Sometimes, this aspiration can also lead to an infection in the lungs, called aspiration pneumonia, which can be also very serious, often requiring hospitalization. For these reasons, I suggest that your son should see a specialist doctor who is trained in dealing with problems of swallowing. In most major medical centers, these specialists are pediatric doctors">otolaryngologists (ENT doctors). There are many reasons to have trouble with swallowing and eating. This can include problems with coordination, nerve problems leading to weakness or dysfunction of the swallowing muscles, and anatomical defects in the throat and voice box. An ENT doctor would be ideally suited to evaluate these problems. Often, they will advise a laryngoscopy, which puts a camera down the throat to see if there are any obvious abnormalities. A swallowing study is also quite helpful; in this study, x-rays are taken while your child is eating, in order to follow where the food is going. Start by setting up an appointment with an ENT doctor. Your general pediatrician can help you arrange the appointment if necessary.