Red and swollen gums and loose teeth may be caused by gingivitis, dental caries, periapical periodontitis, periodontal abscess and other reasons. 1. Gingivitis: usually due to plaque causing a reaction in the gum tissue, under the stimulating effect of inflammation, it can lead to red and swollen gums. If it is not effectively treated for a long time, it may cause loose teeth. 2. Dental caries: clinically also known as tooth decay, usually under the action of diet, bacteria and other factors, resulting in the destruction of the hard tissue of the teeth, which may cause redness and swelling of the gums, loose teeth. 3. Apical periodontitis: usually caused by tooth trauma, bacterial infection, etc. Under the constant stimulation of inflammation, it may cause redness and swelling of the gums and loosening of the teeth. 4. Periodontal abscess: usually caused by diabetes, periodontal pockets lining inflammation, irregular scraping surgery, etc., due to the presence of periodontal areas of suppurative inflammatory reaction, it may cause redness and swelling of the gums, tooth loosening. Gums red and swollen teeth loose, should seek medical treatment as soon as possible, after a clear diagnosis of the cause, to give targeted treatment.