American doctors have described how a patient lost control of the truck he was driving while trying to capture a Pokemon sitting in the road.
Another patient crashed her car trying to avoid a pedestrian who had wandered into the street playing the game.
Researchers say these cases show the potential for "distraction-related injury and death" with the rise in popularity of games such as Pokemon Go.
Both patients were admitted to a trauma centre with serious injuries.
Researchers from the US state of Arizona said it was a challenge to know how to categorise the injuries, which they describe as "augmented reality application related injuries".
The two cases, reported in Oxford Medical Case Reports, are among the first of their kind to appear in a medical journal.
Although the report said these sorts of apps encouraged players to exercise, it also warned of a "sinister side" because they encouraged players to become distracted.
Co-author David Armstrong, professor of surgery at the University of Arizona, said: "Our world is filled with digital distractions increasing at a near logarithmic rate - both in work and in play.
"What we have to figure out as a society and, frankly, as a species, is how to dose these distractions to help make our lives better and not shorter."
He said the key was "striking a happy balance between engagement, activity and distraction".
The first case involved a 19-year-old man who rolled his truck, with three passengers on board, ending up underneath it. He had lacerations to his liver.
One of the passengers was found underneath one of the truck's wheels, which was on top of his chest. He had two wounds to his head.
The other two passengers blacked out but walked away unhurt.
In the second case, a 58-year-old woman collided with a telegraph pole to avoid hitting a distracted pedestrian in the road, and ended up with multiple pelvic fractures.
Recent research from the US suggests thousands of people are playing Pokemon Go while driving.
Police around the UK have warned people playing the game to be aware of busy roads, live train tracks and being fixated by their screens.
What is Pokemon Go?
- It is probably the biggest gaming phenomenon of the smartphone age
- Gamers hunt for Pokemon figures, using their phones' GPS systems and cameras to interact with virtual creatures that appear on the screen as if they were in the same real space as the player
- It launched in the UK in July. One week after its release in the US, Apple said the game had broken the App Store record for most downloads in a week
- Players are typically found staring at their screens while wandering around public spaces, exclaiming about Pikachus, pokeballs and gyms (where Pokemon battle each other)
- There have been lots of reports of people falling over, cutting themselves and walking into things because they are not paying attention to what is in front of them