River crabs are tender and tasty. They also contain more protein than pork or fish. A serve provides lactoflavin, calcium, phosphorus, iron and vitamin A but some people should not eat much crab, or should avoid it completely.

* Hepatitis patients might have problems digesting the rich protein in the crab, which can cause indigestion.

* People with cardiovascular problems should not eat much crab roe because it is rich in cholesterol.

* People with a cold or fever should not eat crab because the protein increase burdens the digestive system.

* People who often have a cold stomach and diarrhea should not eat much crab because it is cold in nature and might exacerbate health problems.

* People with allergies to shellfish

* People who have cholecystitis or gallstone.

* Pregnant women should not eat crabs, because some reports that crab's legs promote blood circulation and can cause miscarriage.

* The Chinese believe that crabs should not be eaten with persimmon, or strong tea, because both contain tannin, which might have chemical reactions with crab protein, and cause indigestion.