Gums bleed when you sip (meaning suck), which can be caused by gingivitis, trauma, medication, blood disorders and other reasons. 1. Gingivitis: most of the gingivitis is caused by plaque stimulation resulting in inflammation of the gums, which will lead to easy bleeding of the gums, resulting in bleeding of the gums when sucking. 2. Trauma: If the gums are stimulated by external forces, such as bumps, car accidents, falls, and recovery from tooth extraction, the gums may also bleed when you sip. 3. Taking drugs: for example, taking aspirin, heparin, clopidogrel sulfate tablets and other drugs caused by adverse reactions, can also lead to bleeding gums when you sip. 4. Blood diseases: thrombocytopenia, coagulation disorders, leukemia, etc., may also cause the gums to bleed when sipping. Bleeding gums when sip, there may be other reasons, need to go to the hospital for examination, clear cause.