A 10-year-old boy has had an HIV test after eating an iced lolly which contained a thick red substance.
He has also had the first of three hepatitis injections and been told he needs blood tests in a year's time.
The boy's mother believes the cola-flavoured lolly, from Sainsbury's supermarket, contained blood.
On this discovery, she took her son back to the supermarket and was told to go to her doctor.
Investigation
The Gloucestershire mother, who prefers to remain anonymous, told BBC Radio: "Any major problem with blood, if it was blood, can show 15 years down the line, this is the worry.
"The congealed mass was on the rim of, and inside, the lolly. It was not colouring."
In a statement, Sainsbury's said it was taking the complaint seriously, but added that it could be difficult to investigate as the ice lolly had melted, and the wrapper thrown away.
The company is promising a thorough enquiry.
The 10-year-old will have to have another blood test in six months time, and another in a year.