Substance abuse means taking drugs (other than those prescribed by a doctor for a specific illness) in amounts that are dangerous or that prevent a person from doing everyday things, including going to school or work. The substance being abused can be alcohol, marijuana, pills called tranquilizers that make people feel very tired or relaxed, household products that are inhaled, or a number of other drugs. Drug abuse happens all over the world, to all kinds of people, young and old. It frequently causes terrible damage to a person’s body, to relationships with family and friends, and to career or education. In some cases, substance abuse leads to death, because the abuser gets involved in an accident or because he or she takes enough of the substance to cause the body to completely shut down.

Exercise is good for your health. Regular physical activity helps a person have stronger bones and muscles, helps control body fat, helps prevent certain illnesses, and contributes to a good outlook on life. Regular exercise helps promote digestion and a good night’s sleep. When children exercise as part of their busy lives, they are better equipped to manage the physical and emotional challenges of a busy day. Many governments and other organizations recommend at least 150 minutes of moderate-intensity physical activity every week.

Edward Jenner, an army surgeon and country doctor from Gloucestershire, England, tried his first experimental vaccination in 1796. At the time, smallpox was a fatal disease that mostly affected infants and young children. Jenner recognized that dairymaids infected with cowpox virus (a minor virus that affected cows) were immune to smallpox. He used material from the arm of Sarah Nells, a dairymaid who had contracted cowpox, to infect James Phipps, an eight-year-old boy. He then exposed Phipps to smallpox, which Phipps did not contract. It worked because cowpox and smallpox have common antigens (proteins), which activated the young boy’s immune system. After repeating the experiment on other children, including his own son, Jenner concluded that vaccination provided immunity to smallpox without the risk of the person contracting the disease. Jenner used the word vaccination for his treatment, which comes from the Latin word vacca, meaning “cow.” Jenner’s findings were published two years later, in 1798; his smallpox vaccine spread rapidly to America and the rest of Europe. Today vaccines are used around the world to produce immunity to disease.

Antibiotics are medicines that help the human body fight bacteria, either by killing the offending germs directly or by weakening them so that the body’s own immune system can fight and kill them more easily. The most widely known antibiotic is penicillin, which is made from mold. Penicillin kills bacteria by interfering with the formation of the cell walls or cell contents of the bacteria.

Germs are everywhere! Most germs spread through the air, invading our homes, pets, and family, and sometimes they make us sick. Besides your bathroom toilet and the kitchen sink, everyday items such as shopping carts, restaurant menus, mobile phones, and shower curtains contain germs. These items contain bacteria, mold, and rhinoviruses (instigators of the common cold) that can lead to sickness. In fact, cold and flu viruses can survive for 18 hours on hard surfaces. Common household items can be swabbed with a disinfectant wipe easily before use in order to prevent germs from spreading. Washing your hands with soap and water, using hand sanitizer, and avoiding touching your face with your hands after using these items also helps keep germs away from you. To eliminate dust mites—those little critters that live in your bed sheets and feed on dead skin cells—don’t make your bed for a while. Studies have found that dust mites need humidity levels above 50 percent to survive and cannot live in the arid conditions of an unmade bed.