Pickled sweet and sour garlic may cause cancer. The process of pickling sweet and sour garlic will produce carcinogenic substances such as nitrate and nitrite, and these carcinogenic substances may cause cancer after they are absorbed into the body. Therefore, it is better to eat less or no pickled food such as sweet and sour garlic, because eating too much of it will increase the chance of getting cancer. It is better to eat fresh vegetables and fruits in daily diet, and to eat less pickled, smoked, and processed vegetables and fruits, because eating too much of them will increase the chance of getting cancer. Eating more fresh vegetables and fruits is good for human body and can reduce the chance of getting malignant tumors.