Hello, There are 3 reasons for bad smell in nose and mouth-- 1.Dental caries or poor oral hygiene 2. acid reflux from stomach ie acidity or heart burn , in addition constipation. 3. Nasal disease- due to nasal discharge that could be allergic , and there are chances of sinus infection . Treatment------- 1.Dental caries or poor oral hygiene---dental doctor opinion , brush mouth 2 times a day. avoid smoking or alcohol 2.acid reflux------- Antacid tablet like proton pump inhibitors with domperidone Syp. antacid gel 2 tsf two times a day half an hour before meals Keep head end of bed elevated. Avoid alcohol, Smoking Do brisk walking daily Go for walk after dinner Avoid spicy food Avoid late night coffee 3.Nasal disease--- Get ENT opinion,, examination of nose needs to be done and if there is suspicion disease then CT scan can be done to see for disease, then further management can be planned. In doubt do reply