Nosebleed

From Lostpedia

Nosebleeds are an occasional side-effect or warning sign of various deaths or injuries on or around the Island, most notably a symptom of temporal displacement.

Result of toxic gas

Nosebleeds were a side-effect of the gas used during the Purge designed to kill the members of the DHARMA Initiative. When Ben opened the gas canister to kill his father, Roger began to bleed from the nose and mouth before dying. When Ben returned to the camp with Richard Alpert, he saw more corpses with blood running down the nose, including Horace Goodspeed. In all, more than 40 members of DHARMA were killed. ("The Man Behind the Curtain") The gas was later revealed to have been released Island-wide from the Tempest station. Daniel Faraday and Charlotte Lewis disabled the station to prevent it from being used to kill everyone on the Island again. ("The Other Woman")

Horace Goodspeed later appeared in a dream of Locke's. As his message repeated, his nosebleed reappeared intermittently. ("Cabin Fever")

Temporal displacement

See also: Temporal displacement

Nosebleeds also seem to be a side effect of time travel that precedes death. George Minkowski and Desmond Hume's consciousnesses traveled through time. Because Minkowski was unable to find a constant between the two time periods, he began to bleed from the nose and later died. Desmond also began to bleed from the nose as well, but survived by making Penny his constant, with the help of Sayid and Daniel Faraday. ("The Constant")

At some point during the construction of the Orchid, one of the workers who was drilling close to the frozen wheel started "grabbing his head and freaking out" and fell to the ground with a nosebleed, unconscious. Dr. Pierre Chang was aware that the frozen wheel was behind the wall and claimed that it was connected to time travel. Faraday, having time traveled from the future, witnessed this. ("Because You Left")

As the Island began to shift in time, Charlotte began to experience nose bleeds. She stated that she hadn't had them since she was a child, presumably on the Island. She also claimed to have headaches and difficulty remembering things, such as her mother's maiden name. Daniel showed concern over this, and Charlotte questioned him about it, but he did not give any answers. ("Because You Left"), ("The Lie")

After the next time jump, Charlotte claimed to be feeling better. However, shortly after making that statement, she began bleeding profusely out of her nose, and collapsed onto the floor, unconscious. Daniel huddled over her and grabbed her in obvious distress and fear moments later. ("Jughead")

Charlotte woke up less than an hour later, but at first did not remember Daniel. She was able to get up and travel with the others across the Island. Two more flashes followed and, while Charlotte showed no more symptoms, both Miles Straume and Juliet Burke began to bleed from the nose. Faraday theorized that the speed at which the nosebleeds begin is related to how much time a person had spent on the Island. ("The Little Prince") Later, Sawyer also suffered a nosebleed after multiple successive time shifts. ("This Place Is Death")