Drugs in capsules are generally powders or granules that are irritating to the esophagus and gastric mucosa, or drugs that have a bad taste, are easily volatile, are easily decomposed by saliva in the oral cavity, and are easily inhaled into the trachea. These medicines are packed into capsules, which not only protect the medicinal properties of the medicines from being destroyed but also protect the digestive organs and respiratory tract. Removing the capsule shell may result in drug loss, drug waste, and reduced efficacy. In addition, some drugs need to be dissolved and absorbed in the intestine, and the capsule protects the drug from being destroyed by stomach acid.

    In order to meet the special needs of the modern pharmaceutical industry for R&D and preparation of new drugs, new types of medicinal hollow capsules with various special functions have come out one after another, including enteric-coated capsules, and vegetable capsules, and sustained-release capsules. According to different plant sources, vegetable capsules can be divided into three categories: starch capsules, hydroxypropyl methylcellulose capsules, and seaweed capsules. Among them, starch capsules use cassava, corn, potatoes, and other plant starch as the main raw materials; hydroxypropyl methylcellulose capsules use cotton, bark, etc. as the main raw materials; seaweed capsules use kelp, horsetail, red algae, etc. as the main raw materials. In comparison, starch capsules have a wider range of raw materials, but their production process is more complex, and production technology needs to be continuously improved in future development.
    In recent years, with the maturity of rubber technology, the application of capsules is no longer limited to the field of health care, and it has also performed well in the beauty industry. Small capsules contain a lot of energy.