And now they are asking you to shop fellow fans if they are seen throwing the "danger foodstuff"
Chelsea have made this statement.
"The throwing of anything at a football match, including celery, is a criminal offence for which you can be arrested and end up with a criminal record.
The Football Association is now investigating referees' reports that celery has been thrown at two recent Chelsea Football Club matches which could result in sanctions being taken against the club.
In future, if anyone is found attempting to bring celery into Stamford Bridge they could be refused entry and anyone caught throwing celery will face a ban.
Your co-operation is requested and if you see anyone throwing celery in the stadium you should report the details on 020 7915 1919. All calls will be treated in confidence."
For those not in the know celery is (Apium graveolens dulce) a herbaceous edible biennial plant in the family Apiaceae, native to the coasts of western and northern Europe, most commonly in ditches and saltmarshes. It grows to 1 m tall, with pinnate to bipinnate leaves with rhombic leaflets 3-6 cm long and 2-4 cm broad. The flowers are creamy-white, 2-3 mm diameter, produced in dense compound umbels. The seeds are broad ovoid to globose, 1.5-2 mm long and wide. Celeriac (Apium graveolens rapaceum) is closely related, being forms of A. graveolens that have "been developed only in the last 200-300 years."[1]
But we all know it as a projectile that's liable to kill ... you have been warned.
Watch out for body searches in the near future as anyone carrying an offensive shirt will not be allowed into their expensivly paid-for seats.
You will have to wear regulation blue only - and then only garments purchased from the club shop.
Anyone caught wearing blue not purchased from the official outlet will be banned from the club and a cardboard cutout replacing you on matchdays will be placed on your expensivly paid-for seat - but only after Chelsea's official ticket touting agency has failed to sell on your ticket ... you have been warned.