Located in the medical room of the ship, alternatively called the Medical Unit, Medi-Bay or Sick-Bay, it helped look after the health needs of the human crew of the ship.
Despite having a full medical staff (such as Chief Medical Officer Karen Newton and her orderly), Red Dwarf was also equipped with an autonomous medical computer capable of diagnosing and treating various ailments. It could monitor vital signs and treat them accordingly.
The original Medicomp seen in Series I appeared fairly inferior (like much of the original Red Dwarf before being rebuilt by the nanobots in Series VIII) and never actually spoke. It is unclear whether the original Medicomp had artificial intelligence.
Rimmer insisted that the Skutters learn how to perform simple medical tasks such as taking a temperature, but Lister preferred to be treated by the Medicomp when he contracted a mutated strain of pneumonia.
The Medicomp was incapable of performing every function. Lister's caesarean section had to be performed by Kryten and the Skutters in the Science Room (RD: Parallel Universe, RD: Backwards, RD: Dad), although this may been because Confidence had earlier smashed up the Medicomp.
In the "lost episode" of Series I, Bodysnatcher (reconstructed in The Bodysnatcher Collection) the original Medicomp has a much larger role. It has artificial intelligence and speaks, and is voiced by Chris Barrie with a lisp. It says that it from Titan and whistles Mexican tunes. When Lister wakes up one day inexplicably bald, he goes to the Medicomp to find out why. It offers him a red, "Lounge Lizard" toupee without giving him an explanation as to why he is bald, and saying it is no different to his real hair, and to which Lister angrily smashes it up.
This new one was called the Medi-Bot and had both a cheerful artificially intelligent interface and an integrated treatment array that allowed it to perform medical care. It spoke with a high-pitched American voice and had a slightly distorted image, showing a man wearing medical garb.
Lister talked to the Medi-Bot about his "Son", David Lister Jr. The Medi-Bot urged Lister to register himself as his own son to receive a raft of benefits. He opened a file for "David Jr." which later proved useful fro convincing Pree that there was more than one human aboard.
The Medi-Bot also had a secondary program called the Denti-Bot. It performed dental surgery for the crew. It spoke with a creepy, German accent that made Lister very nervous (perhaps it enjoyed playing pranks like Holly, or perhaps, also like Holly and the vending machines, it had gone computer senile). Lister refused to allow it to fix his teeth. This may have been due to The Cat taking the last canister of anaesthetic. (RD: Fathers & Suns)
The gang became increasingly became dismayed with the performance of the Medi-Bot, with it apparently suffering from some form of computer senility. When Lister went in for a "rube jab" Lister instead received a "boob job". After bringing Jesus of Caesarea board Red Dwarf and realising that he needed kidney stones removing, Kryten was happy to perform the operation. When Lister questioned Kryten's proficiency at surgery, Kryten informed Lister that he had been performing surgery on Lister for years in his sleep, with Rimmer's permission. Cat ran away to vomit when Kryten told him that he had kept Lister's old organs in a freezer on nearby B Deck, which Cat had been eating. (RD: Lemons)
The Medi-Bot later tried to convince Kryten that if Rimmer made a donation to the medical fund, it would give him a sicknote for his absence from work. When Kryten bribed the Medi-Bot with credits from the sale of the ship's excess toilet paper, it reneged on the unspoken promise. Rimmer managed to convince it that he had been caring for the unstable Lister when he found Lister apparently making love to a vending machine, finally earning a carer's certificate from the Medi-Bot. (RD: Dear Dave)