The reasons are as follows: 1. Hairy crabs and beer are rich in purines, and if both are consumed at the same time, it will cause too much purines to enter the body leading to higher levels of uric acid, which in turn will lead to a high incidence of gout and endanger health; 2. Hairy crabs are rich in protein, which needs to be metabolized through the kidneys, while the metabolism of ethanol in beer also needs to go through the kidneys. The metabolism of ethanol in beer also requires the kidneys. If the two are consumed at the same time, it will cause an increase in the burden of kidney function and endanger health; 3. From the perspective of Chinese medicine, hairy crabs and beer are both cold. If they are consumed in excess at the same time, the balance of yin and yang in the body will be disrupted.