The hardness on the belly button may be caused by epidermal swelling, gastrointestinal dysfunction, constipation, tumor and so on. 1. Epidermal swellings: such as lipoma, sebaceous adenoma, etc., most of which are benign swellings, the larger can be protruding from the surface of the skin, can be touched with a hard feeling, need to consult the doctor in time and excision can be, will not jeopardize the human body. 2. Gastrointestinal dysfunction: such as frequent indigestion, flatulence, intestinal dysfunction, resulting in abdominal distension, intestinal stagnation, can also cause a bit of hardness on the navel performance. 3. Constipation: there is a colon above the navel, long-term constipation, fecal matter accumulates in the intestinal lumen, transverse colon, or when there is accumulation of gas and flatulence, it can be touched and hardened. 4. Tumor: the navel on the colon, small intestine, pancreas, stomach and other organs, long-term neglect, the emergence of large tumors, can be protruding from the surface of the skin, can also be touched harder. Above the belly button seven or eight centimeters press hard also seen in other reasons, it is recommended to seek medical attention in a timely manner, under the guidance of a professional doctor to standardize the treatment, so as not to delay the condition.