Samsung, the world's biggest electronics company, has issued a health warning about the apparent dangers of watching 3D television.
Pregnant women, the elderly, children and those suffering from serious medical conditions are among a wide range of people said to be at risk. The alert extends to those who have been sleep deprived or drinking.
It goes on to highlight alarming side effects such as confusion, nausea, convulsions, altered vision, light-headedness, dizziness, and involuntary movements such as eye or muscle twitching and cramps.
Samsung says there are also concerns that those with epilepsy could be at risk of fits - as they are from strobe lighting and photographers' flashes on normal television.
Watching 3D on TV, which involves wearing special glasses like those used for 3D movies, bombards the eyes and brain with a succession of flashing images that appear for a fraction of a second.
It is a new way of seeing things and so puts unusual strain on the body.
The warning has been posted on a Samsung website and appears designed to protect the manufacturer from any legal claims for compensation if people fall ill.
However, the language could seriously damage the launch of 3D, which is being pushed heavily by manufacturers and broadcasters as a breakthrough.
Samsung's 3D sets are going into stores in the next few days with a starting price around £1,300, while Sony's TVs will go on sale in June.
Other manufacturers say they have studied the health effects of 3D viewing and have decided it is safe to go ahead.
Sky is currently promoting its 3D coverage of premier league football in pubs.
The technology is being driven by a raft of 3D blockbuster films such as Avatar and Alice in Wonderland.
Samsung, based in South Korea, has been the biggest-selling technology brand in the world since 2005.