Some friends will worry because their family members and bladder have bladder cancer and wonder if bladder cancer is contagious and if they can eat with bladder cancer patients. I am here to answer for friends. Bladder cancer is one of the most common malignant tumors of the urinary system, with an incidence rate of about 3-10/100,000 in China, meaning that 3-10 people out of 100,000 will be found to have bladder cancer every year. The main risk factors for bladder cancer include genetic factors, smoking, chemical carcinogen exposure, bladder stones, and Schistosoma egypti. Among these factors genetic factors are not contagious. Genetic factors can lead to family clustering of bladder cancer but are not transmitted from person to person. Smoking is also not contagious, but if someone in the family smokes, other members may be affected by secondhand smoke, and the role of secondhand smoke on bladder cancer is still controversial. Chemical carcinogenic exposure is usually occupational exposure, specific drugs, hair dye, etc., which is also not contagious. Bladder stones are also not contagious. Among these factors, only schistosomiasis egyptii is an infectious disease, but schistosomiasis egyptii cannot be transmitted directly from person to person and requires an intermediate host, so it can only be transmitted in schistosomiasis egyptii infected areas, and there are no schistosomiasis egyptii infected areas in China. Therefore, bladder cancer is not contagious. Friends can rest assured.