Celery

During his fifth incarnation, the Doctor took to wearing a stalk of celery on the left breast of his frock coat. This began after his regeneration when he visited the city of Castrovalva in Andromeda. He considered it as a sign of civilisation. (DW: Castrovalva) While attending dinner as a guest (or captive) of the Eternal Captain Striker, the Doctor replaced his old stalk with a fresh one. (DW: Enlightenment)


 * Rather curiously, both stalks come from buffets which are essentially figments of other people's imagination (Castrovalva and the Eternal's ship both being 'unreal') - although this may explain why the celery never goes off.

Although a later incarnation of the Doctor later dismissed the celery as merely a "decorative vegetable" (DW: Time Crash), the celery may have also served a practical purpose. The fifth incarnation of the Doctor claimed to be allergic to certain gases in the Praxis range of the spectrum, in the presence of which the herb turns purple. In that case, he would eat the celery; if nothing else, he said, at least it would be good for his teeth. (DW: The Caves of Androzani)

The Doctor apparently also believed the celery to possess some restorative ability, as he attempted to revive a dying Peri by having her smell the celery. Her human olfactory sense did not suffice for the plant to help her. (DW: The Caves of Androzani)

When then Eleventh Doctor had been captured by the Silurians, Malokeh attempted to decontaminate him of the surface bacteria, which harms the Doctor. After pleading with the Silurian doctor that he was "not ape", Malokeh stopped the decontamination process. After taking a couple of breaths the Doctor says "That's much better, thanks. Not got any Celery have you?"(DW: Cold Blood)

Behind the scenes

 * While the Fifth Doctor loved celery, Peter Davison hated celery. During a scene in Castrovalva in which he had to eat celery, he spat it out after the first take.
 * The notion of an individual wearing a celery stalk on his lapel did not originate with the Fifth Doctor. In a 1965 episode of The Avengers (a series, coincidentally, created by Doctor Who co-creator Sydney Newman) entitled "Two's a Crowd", an individual impersonating John Steed is criticized for a particularly leafy choice of flower to wear on his lapel. A character remarks that he might as well have worn a piece of celery instead.
 * The theme of having the Doctor wearing something unusual on his lapel was continued with the Sixth Doctor wearing a variety of cat-shaped pins. The Seventh Doctor was also seen on occasion to wear items on his lapel, but not as regularly as his predecessors. By the arrival of the Eighth Doctor, the Doctor's lapels were accessory-free and remain so to the present day.