Jelly baby

Jelly babies were a form of Earth sweet favoured by the Doctor during several of his incarnations.

The the Doctor offered a bag around when he was removed from his time stream to assist with the Omega 'crisis' by the Time Lords when Omega attempted to escape his anti-matter universe, the first time. (DW: The Three Doctors)
During his fourth incarnation, the Doctor was particularly fond of jelly babies and often offered them out.

He offered one to Leela of the Sevateem tribe upon their first meeting, leading her to think he ate babies. He would also effectively bluff the Sevateem by threatening one of the tribe with a "deadly jelly baby" (DW: The Face of Evil)
The Doctor offered round a bag of jelly babies whilst on the sandminer (they were slapped out of his hand while he attempted to do so). (DW: The Robots of Death)
Whilst investigating the Fendahl on Earth he offered "Eustace" a jelly baby in jest. (DW: Image of the Fendahl)
Whilst on Gallifrey as Lord President he requested Castellan Kelner to remove a jelly baby from his pocket for him, in this (slightly power mad state) her preferred an orange one. (DW: The Invasion of Time)
Romana offered a bag of jelly babies around while she and the Doctor are on Zanak. (DW: The Pirate Planet)
The Doctor offered a jelly baby to Davros. (DW: Destiny of the Daleks)
Whilst in the Eden projection the Doctor eats some jelly babies, and also gives a green one missing a leg to Bernice Summerfield (as she was tracking the Key to Time). (DW: Nightmare of Eden, DWM: Time & Time Again)
The Anethans whilst aboard the Skonnonn freighter. (DW: The Horns of Nimon)

The Eighth Doctor also seemed to develop a taste for jelly babies, he also used them to distract a police officer so he could disarm him, whilst in San Francisco. (DW: Doctor Who: The TV Movie)
The Master also appeared to enjoy a bag of jelly babies along side his wife whilst awaiting the Toclafane. (DW: The Sound of Drums)

Behind the Scenes

In the United States, jelly babies had a low as a confectionary product. When Pinnacle Books published Doctor Who novelisations in new packaging, the editorial changes made by them included changing jelly babies to jelly beans, for fear of confusing American readers. Later, when the series had a great deal more popularity, many Americans simply associated jelly babies with Doctor Who and with the Doctor as played by Tom Baker. Under license from the BBC, one company sold jelly babies in packaging resembling the Doctor's TARDIS, advertising them as "the Cosmic Candy of the Time Lords".