Skip navigation

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

URL of this page: //medlineplus.gov/ency/article/002309.htm

Stimulus

A stimulus is anything that can trigger a physical or behavioral change. The plural of stimulus is stimuli.

Stimuli can be external or internal.

An example of external stimuli is your body responding to a medicine.

An example of internal stimuli is your vital signs changing due to a change in the body.

Stimuli include:

  • Irritants
  • Sights
  • Smells
  • Sounds
  • Temperature changes

References

Taber's Medical Dictionary Online website. www.tabers.com/tabersonline. Accessed March 15, 2023.

Review Date 2/2/2023

Updated by: Linda J. Vorvick, MD, Clinical Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.