CNN Health

Doctors don't know what causes Alzheimer's disease or the best way to treat it, but they have new evidence to suggest that a common virus may play a role in who develops the condition.

Koko, the gorilla who mastered sign language and showed the world what great apes can do, has died.

A pediatrician in Colorado examines young children newly separated from their parents and shares her observations with CNN. She says that while their physical condition was fine, emotionally "they were the opposite of stable."

A 9-year-old boy in Greece permanently injured his left eye when he repeatedly gazed into a laser pointer's green beam, doctors say.

With all eyes on the United States and North Korea, experts warn that biological warfare could be more catastrophic than a nuclear attack.

Although he's older than the Giza pyramids and Stonehenge, the 5,300-year-old mummy of Otzi the Tyrolean Iceman continues to teach us things.

A long-awaited government study on the toxicity levels chemicals commonly used in manufacturing was made public on Wednesday, months after a White House official warned that it could be a "potential public relations nightmare."

The World Health Organization no longer classifies transgender people as mentally ill.

Among 16 immigrants deaths in US government detention centers between December 2015 and April 2017, half resulted from inadequate medical care for detainees in times of need, a new report finds.

A 10-year-old Mexican girl with Down syndrome is among the thousands of children who have recently been separated from their parents at the southern US border, Mexico's foreign minister said.

Recreational marijuana use will soon be legal in Canada after the Senate passed a "historic" bill on Tuesday with a vote of 52-29.

The suffering of a 12-year-old boy with epilepsy could lead to the UK legalizing the medicinal use of marijuana, after outrage over his case prompted the government to announce a review.

Almost every American will, at some point or another, face a mental health challenge. It may be related to depression, anxiety, suicidal thoughts, substance abuse or maybe something more circumstantial like grief over a loss or trouble adjusting to a life change. The CDC reports 43.4 million adults suffered from some sort of behavioral health issue in 2015 alone.

Every day, the terrifying reality of a cancer diagnosis changes a child's life. But as technology and treatments improve, many more children could be able to call themselves survivors.