Prophylaxis refers to any medical or public health procedure whose purpose is to prevent, rather than treat or cure, disease. Roughly, prophylactic measures are divided between primary prophylaxis (to prevent the development of a disease) and secondary prophylaxis (whereby the disease has already developed and the patient is protected against worsening of this process).

Vaccines are not technically prophylactic: They are used before illness develops, either being administered to large numbers of people in order to prevent infection, or in some cases (such as the smallpox vaccine) to people who have been exposed to a disease but have not yet become ill. However, by definition prophylaxis only prevents disease while a person is using the prophylaxis. Vaccines prevent disease by allowing a patient to aqcuire an immunity and there is no need to keep taking a vaccine to prevent disease, unlike prophylaxis.

Antibiotics are sometimes used prophylactically: For example, during the 2001 anthrax attacks scare in the United States, patients who were believed to be exposed were given ciprofloxacin. Similarly, the use of antibiotic ointments on burns and other wounds is prophylactic.

Low molecular weight heparin is used as a prophylaxis in hospital patients, as they are at risk for several forms of thrombosis due to their immobilisation.

Health Care Products include any product that the Health Care usus during the treatment of it's patients. This can include anything from simple paracetamol tablets used for getting rid of the symptoms of small aches and pains, to such things as insulin used by diabetics.

Insulin (from Latin insula, "island", as it is produced in the Islets of Langerhans in the pancreas) is a polypeptide hormone that regulates carbohydrate metabolism. Apart from being the primary effector in carbohydrate homeostasis, it has effects on fat metabolism and it can change the liver's ability to release fat stores. Insulin's concentration has extremely widespread effects throughout the body.

Insulin is used medically in some forms of diabetes mellitus. Patients with type 1 diabetes mellitus depend on exogenous insulin (commonly injected subcutaneously) for their survival because of an absolute deficiency of the hormone; patients with type 2 diabetes mellitus have either relatively low insulin production or insulin resistance or both, and a non-trivial fraction of type 2 diabetics eventually require insulin administration when other medications become inadequate in controlling blood glucose levels.