The Island appears to have healing properties that cures inhabitants of defects, disabilities and diseases. Most notably, Locke (paralysis) and Rose (cancer) both believe the Island can heal afflictions. Rose notes in "Lockdown" that Locke's injury will not take as long to heal as Jack and others suggest, presumably due to the healing properties of the Island.
The healed
Jack wounded by the crash of Flight 815
- On Day 1, in "Pilot, Part 1", Jack is wounded in the side. Kate sews up the wound. In later episodes, this wound never bothers Jack.
- However, whilst he was on the beach helping to save people he didn't seem to be effected too badly by it.
- Additionally, the fact that 71 people (48 from the fuselage plus 23 from the tail) survived such a violent crash suggests that the Island may have played a part in their survival. Perhaps all the survivors had fatal or near-fatal injuries, which were healed in the first moments after the crash.
Locke in a Wheelchair
- In "Walkabout", we learn that Locke was paralyzed and started to walk again after crashing on the Island.
- In "Deus Ex Machina", the Island appears to take away Locke’s ability to walk. Locke believes the Island is punishing him and demanding him to complete a task. After he finds the plane filled with heroin and Boone is fatally wounded, he no longer has trouble walking.
- Maybe Locke never had an accident but one day lost his ability of walking due to psychological reasons. Exactly as he lost his voice for almost a day. He just believed that the Island cured him.
- In "The Whole Truth", we learn Jin is sterile and unable to have children. However, we also learn that Sun is pregnant. Sun claims to have slept with no other man than Jin. If this is true, then it would appear to indicate that Jin has been cured of his sterility by the Island. (In the official podcast from ABC, the comi-con edition, a question was asked, who's answer had one of the producers list the healed on the Island. He listed Locke's legs and Rose's cancer-after Rose's cancer he paused and said 'errr'. He did not list Jin's sterile-ness. Which leads to a theory he has not been cured.)
- In "The Glass Ballerina" it was further implied that Jae Lee is the biological father, by placing Sun and Jae in the same bed, nude, appearing to be waking up the morning after.
- It is of note that in "The Whole Truth" the passengers are in Day 58 on the Island. Depending on Sun's menstrual cycle, and Sun's own awareness thereof, it seems that Sun's inquiry for confirmation of her pregnancy likely coincided with her missing of her period. If we can assume that Sun is fairly consistent, an interval of time of nearly sixty days would preclude the possibility of conception occurring before the crash. However, in the 1-in-a-million chance (which seems to happen more often than not on our mysterious island) that Sun conceived a child with Jae Lee before the crash, could be constructed. Let's say Jae has super-sperm that can survive the record setting 8-day lifespan in the female reproductive tract (excluding any island healing effects on in-utero sperm). Jae then theoretically has sex with her the day of the take off from Sydney (a difficult feat as it seems he was already dead at the time... someone else? Sun, you scoundrel!), i.e. day 5 of Sun's menstrual cycle. This would still allow fertilization to happen at the last possible moment for the sperm and the first possible moment for the egg on Day 13 on the Island. If Sun generally had a 28-day cycle, we would expect her to expect her period on Day 23, a little before she revealed she could speak English to Kate in "Hearts and Minds". By all accounts this was a (relatively) peaceful time on the Island, but let's say Sun attributes lateness to the effects of excessive stress (another common occurrence on the Island) for a margin of 3 to 4 days (Day 27 max), and continued to stay in denial for another entire cycle and then some for an additional 31 days... the child could theoretically have been fathered by Jae.
- Day 44, Sawyer is shot on the boat (not on the Island). On Day 48, Jack begins treating the wound. Sawyer, at this point, is unconscious. Sawyer heals rapidly and the following day feels well enough to walk around with Kate. By Day 56, Sawyer acquires the guns in "The Long Con". By Day 63, in "Dave", Sawyer appears fully healed and capable of looting the supply drop and brawling with Hurley.
- In "All the Best Cowboys Have Daddy Issues", Charlie is resuscitated by Jack after being hung by Ethan. This may be considered 'Normal Healing,' yet Charlie was brought back by CPR from a critical or perhaps dead state. The writers purposely gave the impression that Jack had entered into the realm of irrationality with his attempts to save Charlie.
- In "S.O.S.", we learn that Rose is dying of cancer and has very little time left to live. Since crashing on the Island, she’s noticed a difference in herself and believes she has been cured.
- In '"Three Minutes"' Locke gets up and walks normally shortly after his injury from the lockdown.
- None of the survivors seems to have contracted malaria or any other tropical disease as one might expect given the nature of their living conditions and diet.
The unhealed
While the above instances appear to indicate healing properties, there are other examples where people were NOT healed.
- The Pilot, presumably killed by the security system.
- Edward Mars, the US Marshal escorting Kate back to the United States suffers a severe injury to, and has a piece of fuselage sticking out of, his abdomen. Shot by Sawyer and didn’t die. Killed by Jack as an act of mercy.
- Donald, one of the Tailies, died from infection of leg injury sustained from the plane crash on day 5.
- Three additional unnamed Tailies died as a result of injuries received in the crash.
- Joanna, caught in a riptide and drowns in the ocean off the coast of the Island.
- Shannon had asthma. (However, it should be noted that she had no asthmatic attacks after Sun treated her with eucalyptus leaves.)
- Ethan Rom, killed by Charlie.
- Nathan, killed by Goodwin.
- Goodwin, killed by Ana-Lucia.
- Boone suffers a fatal injury when the plane filled with heroin falls from its perch and crashes to the ground. Locke carries him to the Caves where he ultimately dies.
- Shannon, killed by Ana-Lucia.
- Ana-Lucia, killed by Michael.
- Libby, shot by Michael and dies of wounds the next day.
- Kelvin killed in fight with Desmond.
The X-ray of Ben with a tumor
- Benjamin Linus, whose cancer appears to be proceeding at a normal pace. If he has lived on the Island all his life, his spinal tumor should not have grown.
- Ben has a spinal tumor, or cancer of the spine. Locke was healed of a spinal condition (that presumably stopped him being able to use his legs) and Rose of cancer. So therefore Ben has a combination of their healed conditions.
- Ben's condition may have been helped by the electromagnetic field on the Island, and somehow when the fail-safe key was turned, this disruption of the field sped up the growth/detriment of the tumor.
- Ben may spend more time in Otherville/Hydra Island than on the crash island. This may account for the difference.
- Although Locke's condition appeared to be healed immediately after the crash.
Healed, but seemingly at a normal pace
- Ben (aka Henry Gale) is wounded by Rousseau in the shoulder on Day 57. By Day 65, in "S.O.S.", Ben’s wound appears better, but not at the same incredible rate that Sawyer was healed from the gunshot. Likewise the injuries inflicted by Sayid also seem to be healing normally.
- Locke's facial scar over his right eye.
- Charlie's facial scars around (one under and one over) his left eye.
- Aaron's (presumably) routine childhood rash.
Off the Island
- Sarah Shephard is miraculously healed after being operated on by Jack
- Isaac of Uluru is credited with seemingly miraculous cures, though it is possible that he is a fraud.