If you can control the voltage of your laptop CPU and GPU, then it is OK to mine if you undervolt and underclock your laptop. Do not mine litecoin as that can be mined by ASIC.
No, it's NOT as other parts of the Laptop will tend to overheat as well. They flat out ARE NOT DESIGNED for 24/7 operation.
Mining with a laptop is a good way to cause it to die FAST AND EARLY.
Mining Litecoin with ANY computer is a bad idea anyway, guarenteed LOSS doing so for very little Litecoin income.
ASIC is the ONLY way with any Scrypt (Litecoin, Doge, etc) coin, even early ASIC don't make anything any more unless you have SUPER CHEAP electric - then they're breakeven.