Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. To answer your question, yes it is. In fact the American Academy of Pediatrics as well as other important organizations recommend not giving any cold, cough, or allergy medication to any child under the age of four years. This is because of the possibility of side effects. May I suggest an alternative? Put 1-2 drops of saline solution(for example, over-the-counter NaSal Nose Drops) into each nostril to stimulate him to sneeze and cough and blow the nasal mucus to the front of his nose where you can wipe it off. You can do this before each feeding and before each nap. This is very safe and has no side effects. Hope I have answered your query. Let me know if I can assist you further.