Medical Term Definition

Complication

A new medical problem that develops as a consequence of a disease, condition, treatment, or procedure.

A complication may result from the disease itself, from its progression, or from an intervention used to treat it. For example, pneumonia can lead to respiratory failure, while surgery can have complications such as infection or bleeding.

A complication is therefore defined by its relationship to an existing condition or intervention, rather than simply by being another symptom.

QUICK FACT

A complication is not necessarily caused by a mistake. Many complications can occur despite appropriate medical care.

COMMONLY CONFUSED WITH

Side effect: an additional effect of a medicine or treatment that occurs because of the intervention itself; a complication can have many different causes.

SEE ALSO

Clinical & Educational Context

Discussed in Health Articles & Guides

Explore how "Complication" is covered across our evidence-based editorial guides:

4 Articles
Medicine without Jargon

The Best Birthing Position: What Current Evidence Says

Changing maternal position may help in some circumstances, but it cannot overcome every anatomical obstacle or resolve every complication.
The Hard Parts of Medicine

Polypharmacy: What Really Happens When You Take Multiple Medicines

Combining medicines can improve disease control, prevent complications, and help people live longer or with fewer symptoms.
The Hard Parts of Medicine

Do You Need Supplements? What Medical Research Says

Excessive vitamin D intake can cause hypercalcemia, which may lead to nausea, weakness, kidney problems, and other complications.
Cases & Narratives

His Last Malaria: A Case of Suspected Fake Medicines

And there is another complication: once several different medicines have been taken, it can become difficult to reconstruct exactly what happened.