Purple blood vessels at the bottom of the tongue may be caused by the following conditions, such as varicose veins under the tongue, normal phenomenon, poor blood circulation and other factors. 1. Sublingual varicose veins: Sublingual varicose veins are caused by excessive pressure on the sublingual veins, the elasticity of the vein wall is not good, and the venous blood return is not smooth, thus causing the purple blood vessels at the bottom of the tongue, and at the same time there will be deformation and dilatation, and the veins will be bulging and bending. 2. Normal phenomenon: the bottom of the tongue is sublingual caruncle, the mucous membrane is thin and rich in blood vessels, the blood vessels are more clearly exposed, and at the same time, the purple color is presented through the mucous membrane, which is a normal phenomenon. 3. Poor blood circulation: If the body has blood stasis, the blood vessels under the tongue will be purple, accompanied by purple spots on the tongue and dark lips and other phenomena, you can take some drugs to promote blood circulation, such as hematopoietic by blood stasis pills, blood circulation particles, hematopoietic dispersible tablets and other medicines, the above drugs for a long time will lead to coagulation dysfunction, liver dysfunction damage and other adverse reactions, it is recommended that you take them under the supervision of a doctor. The purple blood vessels at the bottom of the tongue are recommended to go to the hospital for examination as soon as possible to find out the cause and timely treatment.