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Drinking liquid nitrogen can lead to serious injury or may be fatal. This is because the temperature of liquid nitrogen at normal pressures is between 63 K and 77.2 K. Although the nitrogen is non-toxic, this is cold enough to cause instantaneous frostbite. While pin-point-sized droplets of liquid nitrogen on your skin won't pose much of a hazard, the extensive contact  get from drinking the liquid would cause severe damage to mouth, esophagus and stomach. Also, as the liquid nitrogen vaporizes, it becomes nitrogen gas, which exerts pressure, leaking into tissues or possibly leading to perforations. Even if the liquid nitrogen vaporizes, the remaining liquid may be dangerously cold.

Although liquid nitrogen is used to make ice cream and other edible science foods, the nitrogen evaporates into a gas before these items are consumed, so it isn't actually present by the time they are ingested.