When you take a pain reliever like ibuprofen, it keeps injured or damaged cells from making and releasing prostaglandin. When the cells don't release this chemical, it means that the brain won't get the pain message as quickly or clearly.
Pain reliever works by holding infected cells of secreting prostaglandin. It is primarily not produced and there will be no stimulus which will happen to feel the pain in the living organism. If someone takes a pain reliever then he will not feel pain because the cells will not send the stimulus to the brain hence the human body will not feel pain. Acetaminophen and ibuprofen are examples of pain reliever that are commonly used.
