Long hours in a car, the lower limbs can appear swollen, medically known as “traveler’s edema”. Therefore, when riding in a car, do not always sit, should always change the position, or stand for a while or elevate the lower limbs to sit for a while, also can be used to massage the lower limbs from top to bottom to help blood flow back. Edema is often one of the important manifestations of certain diseases and can be caused by as many as 30 different causes, most commonly caused by heart, liver and kidney diseases. However, there are some patients with edema who have no abnormal findings by multifaceted examination and laboratory tests, and after long-term observation, the health of these people is not significantly affected. Given that the causes and nature of this type of edema are not well understood, it is medically called benign edema also known as functional edema. Traveler’s edema is mostly seen in people over 40 years of age and fat people, and is more common in women, and it is a kind of benign edema. It manifests as numbness, swelling and heaviness in hands and feet, and edema is more common in both lower extremities and is looser, and hands are often involved; it is mostly mild edema and has little relationship with water intake; edema can disappear completely after rest and position change, often disappearing in the morning and appearing in the afternoon. Travelers edema should pay attention to the following symptoms and the differential diagnosis: 1, malignant edema: is an acute, traumatic, toxic infectious disease caused by Clostridium difficile in a variety of animals. It is characterized by the occurrence of emphysematous edema in diseased tissues, well accompanied by fever and systemic toxemia. The pathogen of malignant edema is mainly Clostridium perfringens. Clostridium edematum, Clostridium perfringens, and Clostridium perfringens can also cause or participate in the pathogenesis. Clostridium perfringens is a two-end blunt bed, strictly anaerobic coarse rod, in vivo and external are easy to form bacilli, bacilli in the center of the thriving body, so that the body is shuttle-shaped. Clostridium perfringens can produce αβγδ four toxins, α toxin for opsin, with necrotic, lethal and hemolytic effect; p toxin for deoxyribose transverse daring enzyme, with leukocidal effect; γ and δ toxins have hyaluronidase and hemolysin activity, respectively. These toxins can increase vascular permeability, cause weaving inflammatory edema and necrosis, and toxin absorption can cause lethal toxemia. Clostridium perfringens is widely distributed in nature, its cell resistance is very strong, the general disinfectant drugs are difficult to short-term effect, but 20% bleach, 3% a 50,6 sulfate carbonate compound, 396-5% sodium hydroxide and other powerful disinfectants can be killed in a relatively short period of time. 2, high-temperature edema: high-temperature edema: in the hot summer months, mild edema of the hands and feet often occurs after outdoor activities. 3. Systemic persistent edema: Systemic persistent edema refers to the accumulation of excessive body fluid in the tissue spaces outside the blood vessels of the whole body and is one of the common clinical symptoms. Edema is a manifestation of systemic qi-chemistry dysfunction and is closely related to the lung, spleen, kidney and Sanjiao organs. It is divided into Yang water and Yin water according to different symptoms, and is commonly seen in diseases such as nephritis, pulmonary heart disease, liver cirrhosis, nutritional disorders and endocrine disorders. 4. Lower limb edema: It is divided into physiological edema and pathological edema. Lower limb edema is clinically common and is mainly seen in the following disease edema. ① Cardiac edema When patients with various heart diseases suffer from cardiac insufficiency, the body circulation is impaired, which reduces the amount of cardiac blood returned to the veins of the lower limbs and causes edema; ② Hepatic edema After hepatic steatosis occurs in various hepatitis, the synthesis of albumin by the liver decreases, resulting in hypoproteinemia and a decrease in plasma osmolality, which can cause edema of the plant limbs; ③ Renal edema In patients with acute and chronic nephritis or nephrotic syndrome, the glomerular filtration function decreases, resulting in water and sodium retention in the body. In addition, a large amount of protein urine is produced, resulting in hypoproteinemia, which causes swelling; ④ Hypothyroidism swelling In hypothyroidism, the patient has mucopolysaccharide deposition in the dermis and accumulation of hyaluronic acid, chondroitin sulfate and water between cells, which can cause swelling of the lower extremities; ⑤ Deep venous swelling of the lower extremities In deep phlebitis or venous valve insufficiency of the lower extremities, the patient may have swelling of the lower extremities due to obstruction of venous return. The patient may have swelling of the lower limbs due to obstruction of venous return.