Smelly armpits but not bad odor may be caused by physiological factors such as improper cleaning, or it may be caused by diseases such as hyperhidrosis. 1. Physiological factors: If the local cleaning is not in place, it may cause sweat or bacteria to remain in the armpits, which can lead to not bad breath, but armpit odor. 2. Hyperhidrosis: the etiology may be related to autonomic dysfunction, infection, drugs, malignant tumors and other factors, temperature changes, alcoholism and other causes can also trigger the disease. The main manifestation is an abnormal increase in sweat, inducing local odor, erythema, etc., commonly found in the palms of the hands, armpits, soles and other parts of the foot. If there is a smell in the armpits but not the case of fox odor, after excluding physiological factors, you should go to the regular hospital for examination to clarify the cause of the disease.