Medicines and medications have been developed for many years to treat many different diseases. Vaccinations have been carried out to treat large epidemics, such as smallpox and, more recently, the H1N1 virus. Over-the-counter medications have been produced to help reduce acid reflux and bloating. Despite these discoveries, there are still many drugs that have yet to be produced to treat diseases such as cancer and AIDS. When pharmacists study medicine and drugs, it is important for scientists to understand how drugs are used to help the body function. Microorganisms attack billions of humans and animals every day. These microorganisms are known as invaders. These invaders cause the body to respond with different lines of defense. Examples of nonspecific defense mechanisms are skin, mucus, white blood cells, and blood clotting that defend invaders. Examples of specific defense mechanisms are antibodies and memory cells. Another phrase for medicine and drugs is pharmaceuticals. These products include different types of medicines and medications. A drug is “a chemical substance that affects the functioning of the body” (Brown). A drug will change the body in a negative or positive way. Drugs like heroin and cocaine could essentially harm the body. A medicine is “a substance that improves health” (Brown). Medicines usually have a therapeutic effect on the body because they are beneficial drugs. In general, "medicine or drug is any chemical substance that alters physiological state, including consciousness, level of activity or coordination, incoming sensory sensations, or moods and emotions" ("Option") . The placebo effect is a controversial topic that has been used as a therapeutic drug that is not really a drug. The patient believes he is taking a... middle of paper ......nter. Network. 19 February 2012. "Antibacterials". Network. February 19, 2012. .Brown, Catrin and Mike Ford. Higher Level Chemistry: Developed specifically for the IB Diploma. Pearson, 2009. Print."Depressants." Network. February 19, 2012. "Drinking in America: Myths, Reality, and Prevention Policy." Network. February 19, 2012. "Option D: Medicines and Drugs." International Baccalaureate Organization 2007. Web. 18 February 2012. "Why excessive use of antacids can be dangerous | Heartburn no more." Heartburn No More: Does It Really Work? Read the user review! Network. February 19. 2012. .