Placebo (placebo effect)
A placebo is any substance that is not known to have any pharmacological effects (produces no meaningful changes in an oranism, either chemical, biological, etc.) that is made to look like an active ("real") drug. Sometimes the act of taking a pill produces an effect if the person believes the pill is active. To compensate for this, scientists often give placebos to determine if an effect is due to the "real" drug or from the act of just taking a pill. For additional information, see Control Condition.