Scientists have proved that some alternative therapies have healing powers. One common type of them is using scents. Pleasant smells work in various ways: some help calm stress, some relax people, and others bring up people's energy. Popular scents include fruit, grasses, and flowers. Japanese engineers have designed aroma systems in public buildings. They put different scents into the air to create a better environment. For example, customers who are waiting in long lines at some banks might smell fresh flowers and feel more at ease. Animals are also believed to have abilities to calm and comfort people, especially young patients in hospitals and older people in nursing homes. The animals are brought to these places for ill or injured people to see and touch. This has an amazingly soothing effect. Dogs and cats are the most usual healers, followed by rabbits and birds, and sometimes deer, horses, and even llamas are used! Colors can change your mood and emotions, too. Medical experts skilled with colors believe that colors around you have varied effects to you. For example, the color blue can relieve pain, and the colors red and orange can make you energetic. Some therapists even believe different parts of the human body are influenced by different colors. They believe that having the right colors around you can help you get better when you are sick. It is also reasonable that amusing things can give you a pleasant mood or a good laugh. Laughter reduces stress, fear and anger. Many hospitals encourage their nurses to smile to and laugh with their patients, or put funny pictures on the walls. In India, there are "laughing clubs" for people to get together in the morning to tell hilarious stories to start the day, as many believe laughter is often the best medicine.