A woman said she felt "disgusted" and "shaken" after being served a Subway sandwich with an earwig inside it.
Maryam Khan was with her aunt and three cousins at the fast food shop in East Midlands Designer Outlet, South Normanton, on Sunday.
The 21-year-old said she started "panicking" after discovering the bug in one of the sandwiches the family was sharing.
A Subway spokesman said the shop's suppliers "have been notified".
'Disgusted and shaken'
Ms Khan, from Mackworth, said she and her family "were so scared" because they initially thought it was a cockroach, before they were told by the manager it was an earwig.
"We felt really disgusted and shaken by it," she said.
"What if we'd ended up eating one of the insects?"
A spokesman for Subway said the outlet had a five-star food hygiene rating but confirmed "an earwig was found in the lettuce".
They added: "The store ensured the guest received a full refund for her meal, as well as immediately replacing these with two new freshly-made subs."