In the drug study, some participants took real medication while others were given only placebos.

placebos 是 placebo 的复数形式，placebo 来自拉丁语，原意为"我将取悦"，在医学领域指"安慰剂"，即不含有效药物成分的制剂，用于对照实验或满足患者心理需求。