<s>[INST] my three year old son has a bad constant cough with a runny nose i have been taking him to the doctor everyother week and they keep giving him steroids but nothing is working. i have taken him to an allergist and they said he might have asthma and also took him to get checked for allergies nothing came up. he seems to cough the worst at night time when he sleeps [/INST] Hello, Welcome to Chat Doctor, The history and symptoms of your son suggests me that he may be having some trachea bronchial spasm which is producing all these symptoms recurrently. The precipitating factor for the spasm should be found out to treat the condition adequately. As you have taken your son to the allergist for testing for the most prevalent allergens and the test has come negative. I would suggest you to give1. Oral antibiotics like Tab Autoclave 375 mg, twice daily for 5 days2. Spy Ale rid D3. Small dose of oral steroids for 5 days4. Syp Bicarb A.This medicine will improve your sons condition. Thank You. </s>