Can leeches be used to treat varicose veins? The simple answer is no. This applies to all CAM (Complementary Alternative Medicine) ‘treatments’ for varicose veins. Varicose veins need proper scientific investigation and management. Clinics offering such treatments are at present subject to formal complaints. Leeches suck the blood out of veins, which, from a pseudoscientific view, may sound sensible; but if blood is drained from a vein and nothing done to kill the vein wall, it will just fill up again. A further downside, apart from the fact that leeches will have no beneficial effect, is the damage they can cause. See below photo of a patient who has had leech treatment. It clearly shows that the veins are still there but also the scars from where the leeches latched on to the skin.