Mark Griffiths, professor of gambling studies at Nottingham Trent University, says they can be a distraction for children undergoing painful treatment.
Writing in the British Medical Journal, he added that games can also help children with attention deficit disorders gain social skills.
But he said violent games, like violent films, might fuel aggression in some.
However, Professor Griffiths said this group could be prone to aggression, which could have been triggered by other factors such as witnessing violence in the home or seeing it on TV.
After 15 years of research into video games, Professor Griffiths said he wanted to redress the balance of public perception of their effects.
He said games could be used as a very powerful form of distraction for children undergoing painful treatments.
He said they needed less pain relief and had less nausea and lower blood pressure than those who were simply told to rest after their treatments.
Professor Griffiths also highlighted specific cases where video games had been used to help treat specific physical conditions, including an eight-year-old boy whose illness caused him to pick his lip, causing scarring.
"Video gaming is safe for most players and can be useful in healthcare.
"Although playing video games is one of the most popular leisure activities in the world, research into its effects on players, both positive and negative, is often trivialised."
He added: "On balance, there is little evidence that moderate frequency of play has serious adverse effects, but more evidence is needed on excessive play and on defining what constitutes excess in the first place.
"There should also be long-term studies of the course of video game addiction."
"Video games are always used as a scapegoat for concerns.