Four ecstasy pills have been found inside a computer game bought at a High Street store.
Richard Thornhill, 34, found the drugs under the front cover of X-Box game Grand Theft Auto IV, which he bought from Gamestation in Cheltenham.
Mr Thornhill said: "What made me feel the most distraught was the fact we let our 12-year-old play the game."
A spokesman for Gamestation said the company has launched an investigation and was assisting a police inquiry.
But the Thornhills claim Gamestation's initial response was to tell them to "flush the drugs down the toilet".
Mr Thornhill said he bought a second hand, or pre-owned, copy of the 18-certificate game before making the discovery last Sunday......
I bet that ecstasy is worth a whole copy of the game now, I wouldn't be pleased if I left that.