Banana

Bananas were an Earth fruit. They were a good source of potassium. (TV: The Doctor Dances) Bananas were commonly associated with monkeys. (TV: Ghost Light) They included vasoactive amines, which made some people such as Toshiko Sato vomit. (TV: Something Borrowed)

According to the Ninth Doctor, a banana grove grew in Villengard on the former site of the weapons factories. (TV: The Doctor Dances)

The Doctor
Jo Grant brought a captive Ogron a banana. He did not comprehend her instructions to peel it. (TV: Frontier in Space)

On Space Station Chimera, the Sixth Doctor found a banana whilst searching his pockets for piece of wire. He gave the banana to Peri, who later started to eat it, but gave up when the sight of a dead Androgum made her feel sick. (TV: The Two Doctors)

The Fourth Doctor expressed a fondness for bannanas, once stopping an alien fleet with one. (COMIC: Death to the Doctor!)

The Ninth Doctor also expressed his fondness for bananas and briefly switched one with Jack's sonic blaster to stop him from shooting at Jamie. (TV: The Doctor Dances)

The Tenth Doctor also liked bananas. He claimed that while partying with Madame de Pompadour in 18th century France, he might have invented the banana daiquiri several centuries early. He also offered Rose the advice, "Always bring a banana to a party". (TV: The Girl in the Fireplace) He also liked banana milkshakes. (TV: Smith and Jones) When he tried to stop Sky Silvestry from copying him, one of the things he mentioned was a banana. (TV: Midnight) During a visit to Blackwood Falls, the Tenth Doctor ate two banana splits in quick succession. (PROSE: Forever Autumn) He described a "Banana Surprise". (PROSE: Martha in the Mirror) Once, when expecting to land on a sunny beach, he emerged from the TARDIS with an inflatable banana. (PROSE: Snowglobe 7)

The Eleventh Doctor started to use the idea of a banana in an attempt to explain to Rory that the TARDIS had entered conceptual space. (TV: Space) During a visit to ancient Egypt, he overturned a stall selling bananas while his companions and he were being chased. (COMIC: Assimilation²)

And, in 1938 Berlin, the Eleventh Doctor switched Melody Pond's gun with a banana to foil one of her attempts to kill him. (TV: Let's Kill Hitler)

Others
Reverend Ernest Matthews was given a banana by Josiah Samuel Smith just before Josiah turned him into an ape. (TV: Ghost Light)

Duncan Goode told Martha, "Don't judge a banana by its skin". (PROSE: Wishing Well)

Eugene Jones favoured banana milkshakes. (TV: Random Shoes)

After being defeated by the Tenth Doctor, Bob Kreesus slipped on a banana skin and fell over a cliff edge. (COMIC: Triskaidekaphobia)

When Ianto Jones was explaining automatic doors at the supermarket to Diane Holmes, John Ellis and Emma-Louise Cowell, the women were distracted when they spotted bananas. They were very excited to see so many on display, indicating bananas were difficult to come by in 1953. (TV: Out of Time)