It is best not to eat crab during menstruation for the following reasons: first, crab is a cold food, eating crab during menstruation may lead to cold invasion, dysmenorrhea and other problems, many women are weak during the onset of menstruation, eating crab may lead to abnormal problems, such as the emergence of various disease reactions. Secondly, women who are usually more prone to allergies may have more intense allergic reactions if they eat crab during their menstrual period, so it is best not to eat food such as crab, and it is also best not to smoke or drink to avoid affecting the normal body metabolism. Thirdly, eating crab during menstruation may lead to stagnation of blood and stasis of the menstrual blood, which may lead to reflux of the menstrual blood and blockage of the fallopian tubes, so it is best not to eat crab during menstruation.