I do not think that, short of terrorists adulterating our precious jelly bean supply that it is possible to overdose on jelly beans!(Intercom) Calling Dr Imp, calling Dr Imp....report to ER for a possible jelly bean poisoning!
However, Sedum rubrotinctum, commonly known as the Jelly Bean Plant, is poisonous.
Why anyone would name a poisonous plant after nature's most perfect food is beyond me.