MedlinePlus

MedlinePlus is a service of the National Library of Medicine (NLM), the world's largest medical library, which is part of the National Institutes of Health (NIH). It was built as an online health information resource for patients and their families and friends.

MedlinePlus presents high-quality, easy to understand, relevant health and wellness information that is trusted.

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MedlinePlus at a Glance

Offers information on health topics, human genetics, medical tests, medications, dietary supplements, and healthy recipes.
Sourced from more than 1,600 selected organizations.
Provides 40,000 links to authoritative health information in English and 18,000 links to information in Spanish.
In 2018, 277 million users viewed MedlinePlus more than 700 million times.

Secondhand Smoke

Secondhand smoke is a mixture of the smoke that comes from the burning end of a cigarette, cigar, or pipe, and the smoke breathed out by the smoker. It contains more than 7,000 chemicals. Hundreds of those chemicals are toxic and about 70 can cause cancer.

Health effects of secondhand smoke include:

Ear infections in children
More frequent and severe asthma attacks in children
Heart disease and lung cancer in adults who have never smoked

There is no safe amount of secondhand smoke. Even low levels of it can be harmful. The only way to fully protect nonsmokers from secondhand smoke is not to allow smoking indoors.

Centers for Disease Control and Prevention