The Doctor's TARDIS had a laboratory.
The laboratory was around the size of a school assembly hall, when Barbara Wright visited it once. It had lines of long wooden benches covered with a variety of scientific instruments, from Chinese abacuses, to test tubes, to items from Barbara's future she didn't recognise. It also had a wall lined with computers, another wall with diagrams and charts, and a third wall with huge shelves full of files, papers, and books. (PROSE: The Edge of Destruction)
While staying in London, on 31 March 1963, Susan came home from school and tried to find the Doctor. She searched both his laboratory and the control room, but found him in neither. (PROSE: Time and Relative)
During the time the TARDIS was immobilised and everyone was acting strangely, Barbara Wright found the TARDIS laboratory. There she was assaulted by books, boxes and various bits of equipment from the benches. (PROSE: The Edge of Destruction)
While in Greenland in 1002, the Doctor gathered several tools and items from his laboratory for plutonium collection, including a chisel, pocket geiger counter, compass and a lead-lined container. (PROSE: Who Discovered America?)
Amy and Tony Barker once accidentally stowed away in the TARDIS, and unintentionally locked themselves in the Doctor's laboratory. Later, the TARDIS landed on the Sense Sphere, and the First Doctor used his laboratory to synthesise prussic acid, which he then used to kill a Zilgan. Unbeknownst to the Doctor, Tony had been observing him from underneath a bench in the laboratory. (PROSE: The Monsters from Earth)
The Second Doctor and Victoria Waterfield ran experiments in the TARDIS laboratory on fragments of a Weed creature, which was invading a sea gas refinery. Jamie McCrimmon noticed “Wriggly things” in one of the experiments, leading the Doctor to conclude that the weed was just as much alive as they were. This is the first time the TARDIS laboratory is seen on screen. (TV: Fury from the Deep)
When Ace was new on board the TARDIS, she explored its interiors and found the lab. She thought it was similar to Frankenstein's lab, but with better lights. Ace didn't tell the Seventh Doctor she found it, because she knew he'd lock it up to keep her from making Nitro-9. She couldn't always find the place afterwards. (PROSE: Echo)
Ahead of Christmas dinner on board the TARDIS with Susan Campbell and her son Alex Campbell, the Eighth Doctor visited the TARDIS laboratory to examine Alex's DNA. Looking at Alex's hair through his equipment, he discovered that only 7% of his great-grandson's genome was Gallifreyan.
When the Tenth Doctor found himself warring against the Kotturuh in the Dark Times, he used the laboratory to analyse a sample of their genetic material and devise a way to make it vulnerable to their own necrotic retro-virus. (PROSE: The Knight, The Fool and The Dead)
The Doctor who visited Karn with Jenny Wilson and Jimmy Forbes altered one of the fragments of the Crystal of All Power in the TARDIS laboratory while it was in his possession, thereby sabotaging the Daleks' intended use of the Crystal. (AUDIO: Seven Keys to Doomsday)