Pregnant women, drunk people and "those who are sleep deprived" should not watch 3-D television because of potential health issues, electronics manufacturer Samsung says on its Web site.
The company also says people at risk for stroke or epileptic seizures should consult a medical professional before watching TV in three dimensions.
Samsung and Panasonic began selling the first 3-D TVs in the U.S. last month.
The warnings come as other TV manufacturers are set to debut 3-D home entertainment systems this year. When watching 3-D TV, users wear special glasses with lenses that open and close rapidly to produce an image that appears to leap off of the screen.
Some of Samsung's warnings apply to everyone:
"Viewing 3D television may also cause motion sickness, perceptual after effects, disorientation, eye strain and decreased postural stability," the Web site message says. "It is recommended that users take frequent breaks to lessen the potential of these effects. If your eyes show signs of fatigue or dryness or if you have any of the above symptoms, immediately discontinue use of this device and do not resume using it for at least thirty minutes after the symptoms have subsided."
The TV maker also says wearing its 3-D glasses in normal situations, when you're not watching 3-D TV, "may be physically harmful to you and may weaken your eyesight."
The warning suggests that some 3-D TV viewers could become so disoriented that they could fall and hurt themselves:
"Viewing in 3-D may cause disorientation for some viewers," the warning says. "Accordingly, DO NOT place your TV television near open stairwells, cables, balconies, or other objects that can be tripped over, run into, knocked down, broken or fallen over."