A stimulant drug will temporarily speed up some processes in the body, such as make the heart beat faster and increase blood pressure.
People can do things more quickly, like think, move and speak. They may feel in a better mood and/or more confident. They will feel very awake and on top of things but they may also feel agitated or anxious.
Some people might drink coffee or energy drinks to help stay awake or concentrate.
Those who regularly use stimulant drugs like cocaine and speed are at risk of becoming dependent on them, making them want to use more, more often and this can have a negative effect on their health.
Stimulant drugs can also cause anxiety and heart problems if they are regularly used.