Which internal organ causes swollen and painful gums due to excessive internal heat?

Gingival swelling and pain may be related to excessive internal heat in several organs, primarily involving excessive stomach fire and kidney yin deficiency with fire hyperactivity. 1. **Stomach Fire**: When excessive heat is present in the stomach, the pathogenic heat may travel upward along the stomach meridian (Foot-Yangming) to the gums, causing severe redness, swelling, heat, and pain in the gums, accompanied by symptoms such as bad breath and thirst. In such cases, treatment should primarily focus on clearing heat and purging stomach fire. 2. **Kidney Yin Deficiency with Fire Hyperactivity**: If kidney yin is deficient, the resulting deficiency fire may ascend to the gums, causing gingival swelling and pain, although the pain is generally milder. Patients may also experience dizziness, tinnitus, night sweats, and heat sensations in the palms, soles, and chest. Treatment should primarily aim to nourish yin and reduce fire. Gingival swelling and pain may be caused by either excessive stomach fire or kidney yin deficiency with fire hyperactivity. Specific diagnosis and treatment should be determined by a professional TCM practitioner through pattern differentiation.