Freshwater crabs are used separately or together with herbs like ginger and purple perrila leaf by traditional doctors to treat various diseases.
According to traditional medicine, freshwater crabs have a cooling effect on the body. They can also remove hazardous matter from the human body, strengthen bones and tendons, prevent blood clots, relieve the muscles, get rid of pimples and swellings and muscle inflammation, treat fevers as well as indigestion.
Freshwater crabs can be used separately or together with some other herbs to treat different diseases.
To make babies stronger and learn to walk early, people traditionally use the body of the crab, fry it slowly without fat or oil till it turns yellowish brown and dry, then pound it into powder and sieve it to get only a very fine powder.
Every day, they use this powder (1-2 teaspoonfuls each time) to mix with rice flour and water to feed babies.
To treat rickets in children, about 100g of freshwater crabs are pounded and squeezed to get the juice, which is then used to cook rice gruel and fed to them every day. For this problem, it is also advisable to have the children out in the sun two or three times a week.
To treat bruises caused by falls or accidents at work, traditional medicine doctors advise a combination of 30g of the crab shells and legs (already fried to yellow brown), 10g of xuyên khung (radix chuanxiong), 20g of tô mộc (lignum sappan), 10g of ngải diệp (folium artemisiae argyi), 16g of kê huyết đẳng (caulis mucunae), 18g of nam tục đoạn (radix dipsaci), 20g of thổ phục linh (rhizome smilacis), 16g of cỏ xước (twotooth achyranthes), 16g of buởi bung (glycosmis citrifolia), 16g of đinh năng (radix caulis), 8g of quế tâm (cinnamon) and 10g of cam thảo (liquorice). All these are cooked to make tea for daily consumption. It is said that this tea can help heal bruises clear blood vessels, reduce pain and relax muscles.
Freshwater crabs are cooked with bittergourds to make a soup that can treat toothache and pain in the gums because of excessive heat in the body.
Avoid them when:
Since freshwater crabs can help remove blood clots and heal bruises, traditional medicine doctors advise pregnant women not to eat them.
Those who have just recovered from a sickness should also avoid them because their digestive system is not very healthy yet. Those who know what their spleen and or stomach are not in good condition as well as those suffering from diarrhea should refrain from eating freshwater freshwater crabs.
Crab roe contains a lot of cholesterol, so people with hypertension and cardiovascular diseases should consume very little of it. Freshwater crabs also have a high sodium and purine content, so they are not good for people with gout.
Also, some kinds of freshwater crabs should be avoided by everyone. In the medicine book Nam dược thần hiệu (Southern herbs are magic), Physician Tue Tinh notes: “It is important to avoid eating freshwater crabs which have six or four legs, red eyes, hair on their belly or have bones in their belly, starry dots on their back and head, and stripes on their legs. These can cause allergic reactions, so people should be careful.”
Some people prefer to eat freshwater crabs raw or cooked rare, but this is risky because parasites in the crabs can enter
the body and cause parasitic diseases.
Traditional medicine practitioners also advise that freshwater crabs are typically eaten with gừng (ginger) and lá tía tô (purple perrila leaf) to partly reduce the cooling effect they have on the body.