Tesco has been forced to recall one of its own-brand cordials after receiving complaints about a "disgusting smell".
The supermarket giant confirmed it had withdrawn its Tesco No Added Sugar Double Concentrate Apple and Blackcurrant 750ml and 1.5-litre products after a flavour additive was added "in error".
Tesco said it did not pose any food safety risk, but admitted that the additive has a "strong odour - similar to garlic, which customers are likely to find unpleasant".
But some parents raised concerns that it may have caused their children's stomach upsets after those who drank the squash were left vomiting or with "bad bellies".
Responding to a post on the PlayPennies website, which alerted users to the recall, one user said that it smelled "absolutely disgusting" and others described the drink as smelling like "rotten eggs".
"The only away to describe the smell was it smelt like it had been mixed with used toilet water," Chez79 posted.
Another wrote that "the smell was horrendous, but drank it anyway as I thought they just changed it". Claredavies85 added: "Since then, both my daughter and partner have had bad bellies."
Others also wrote that their children had suffered from vomiting and diarrhea after drinking the cordial.
@tanyacouchman The product contains dimethyl disulphide its an ingredient normally used in savoury products to impart a garlic odour. 1/3; Tesco (@Tesco) January 29, 2015
Swilly26 said: "I gave this to my son on Sunday then Sunday night he was sick. He's had some more today and been sick again - this sounds very strange to me."
And MrsD32 claimed: "We finished a bottle of this yesterday and opened a new one last night. My eldest 2 children are off school today, one with diarrhoea and the other was sick all night. I hope this is a coincidence Tesco!"
@Sammyjodicken Hi Samantha, this is a concern, we have been assured that there is no food safety risk from consuming this product, 1/2; Tesco (@Tesco) January 29, 2015
A Tesco spokeswoman said: "We have investigated with our supplier complaints about Tesco No Added Sugar Double Concentrate Apple and Blackcurrant 750ml and 1.5l.
"A flavour additive, which is not part of the ingredients for this product, has been added in error. The additive is called Dimethyl Disulphide and is a common ingredient in food products.
"It is an approved additive and poses no food safety risk. However, it does have a strong odour, similar to garlic, which customers are likely to find unpleasant.
"Only products bought since the New Year may be affected, they will have a best-before date of October 2015.
"Any customers can return this product, open or unopened, to any Tesco store."
The Food Standards Agency has not issued an alert.