天然肠衣是用家畜的大、小肠经刮制而成，较坚韧、半透明。天然肠衣弹性好，保水性强，市民可放心食用。品质优良的猪肠衣质地薄韧，透明均匀（羊肠衣以厚为佳）。
The natural casing is made of large and small intestine, which is stronger and more transparent. Natural casing elasticity is good, protect the water is strong, the citizen can be comfortable to eat. The fine quality of the casing of the pig casing is very strong and transparent.
人造肠衣的弹性、伸缩性和透气性都较差，填充量也是固定的，高温下有塑胶异味。
The elasticity, scalability, and breathability of the artificial casing are poor, and the amount of filling is also fixed, with plastic odors at high temperatures.
人造肠衣又分为三类：一是纤维素肠衣，用天然纤维如棉绒、木屑、亚麻和其他植物纤维构成，不能随肉馅收缩，不能食用，可作大、小红肠的包装，如火腿肠的外包装。二是胶原肠衣，是以牛、猪真皮层的胶原蛋白纤维为原料制成，色泽呈半透明米黄色，形状呈无缝管状，无破孔，其性质与天然肠衣类似，这是人造肠衣中唯一可以食用的。三是塑料肠衣，用聚乙烯膜、聚丙二氯乙烯制成，只能蒸煮，不能食用。由于人造肠衣较便宜，且可大量生产，目前在市场上仍占一定比例。
Artificial casing is divided into three types: one is the cellulose casing, with natural fibers such as cotton wool, wood chips, linen and other plant fiber, not with meat contraction, not edible, can make large and small sausage packaging, such as sausage packaging. Second, collagen casing, with cattle, pigs dermis collagen fiber as raw material, translucent color beige, shape is seamless tube, no broken hole, its property is similar to natural casing, this is the only edible in artificial casing. Three is plastic casing, made from polyethylene film, polypropylene dichloride, can only be cooked, not edible. Because synthetic casing is cheaper and can be mass-produced, it still accounts for a certain percentage of the market.
食安办专家建议，最好去大中型超市或较大集贸市场中的合格灌肠点，选用天然肠衣进行灌肠。天然肠衣与人造肠衣相比有着不可替代的优势，不仅食用安全，而且未经高温蒸煮，营养也更丰富。
The expert suggests that the best go to the qualified enema in large or medium-sized supermarket or large market, and choose the natural casing for enema. The natural casing has an irreplaceable advantage over the artificial casing, which is not only safe, but also more nutritious and uncooked.