The numbness of the left side of the gums, may be the left side of the gingivitis, or dental disease, as well as improper diet, abnormal neuromodulation and other reasons. 1. Gingivitis: most of the plaque caused by gum inflammation, may cause the left side of the gum numbness and other symptoms. 2. Dental diseases: For example, tooth decay, pulpitis, periapical periodontitis and other dental diseases can also cause numbness of the left side of the gums. 3. Improper diet: such as tobacco and alcohol stimulation, taking spicy food, too hard, too acidic ingredients, may stimulate the gums and lead to numbness of the left side of the gums. 4. Abnormal neuromodulation: Abnormal neuromodulation caused by various reasons may also cause numbness of the left side of the gums. The left side of the numbness of the gums, there may be other reasons need to go to the hospital in time to check, follow the doctor’s instructions for treatment.